Groups are fun, but traveling solo has a lot of advantages - you meet more people, make your own schedule, and have more freedom. Freedom is what motorcycling is all about for me, so I do a fair bit of riding by myself.
Being on your own comes with some inherent risks however, especially when doing an already risky activity such as riding a motorcycle. Here are some general tips that may be helpful to consider.
I keep these in my head as a ride to keep myself out of trouble:
Don't attempt anything you're not at least 95% sure you can make it through without getting stuck or crashing. This entirely depends on your skill and your bike, so it's up to you to make this decision on a case by case basis. If I come to a creek, mud hole, rock garden, or hill, log, or similar thing that I'm not at least 95% sure I can make it through with no issues - I turn around. Getting a 500+lb bike stuck in the middle of nowhere by yourself can take a lot of time to undo. If you don't know what your limits are, it's probably best to test them somewhere close to home, but if you come to something on an adventure ride, and you're feeling nervous, that's a sure sign that you maybe shouldn't try it.
Don't ride down anything you're not 100% sure you can ride back up. This is a very important sub-rule to keep one from getting stuck down in some valley with no way out. Sometimes I'm going to get off the bike and walk down the hill to scope it out before riding it.
Don't use more than 1/2 tank of fuel. This ensures that I can always get back to the last gas station I used. Once you get West of about Kansas in the US, things really spread out, and some gas stations that are on the map may not be there anymore.
Don't ride further in than you can walk out. If I'm riding into something challenging for my abilities and remote, like into a series of Forest Service trails for example, I make sure that I'm not further away from a main road than I can reasonably hike out in a day or two. For me, this is about 20 miles, but that's based on personal fitness and comfort level... keeping in mind that you might be hiking in MX boots.
Things which I recommend having or doing to make traveling solo safer and more enjoyable:
Mindset. Get ready for an adventure! Things will go wrong and in a way this is what it's adventure riding is all about. Expect and embrace the unexpected.
Time. Plan your days so you have plenty of time to deal with anything unexpected. This will drastically reduce your stress levels when the unexpected inevitably happens.
As a general rule I try to never ride early in the morning or after sunset. Too much potential for deer or other deer-like animal encounters.
Money. As with any travel in general, having access to funds in a variety of different ways is important. Cash, a couple credit cards, some checks...etc.
Communication. Have an emergency off-the-grid communication device such as a SPOT, inReach, or ACR PLB in addition to your cell phone. Frankly cell coverage is getting very good in even very remote places these days, but it's still not 100%. I use and recommend an inReach personally, a big advantage of it is the two way communication, and the tracking feature, so you can have someone keeping an eye on you remotely if needed.
Make sure your SPOT, inReach, or other emergency communication device is somewhere on your body where you can get to it in case you are injured. Don't have it on your bike as in most crashes you and your bike will not stay together. Having the device in your chest area is typically recommended as getting into a backpack while injured can be difficult.
Navigation. Having accurate offline maps of where ever you're going is critical. If you're using your phone, make sure the maps are cached locally on the device, and you're not relying on cell service. If you're riding in an ORV area or National Forest or something not intended for normal cars, road maps (i.e. Google maps) are not enough. You'll want a map specific to that area, and/or a very good topo map. Using a GPS unit (Garmin or whatever) can be a good idea since most of them will make a track as you go, which you can follow back out if needed. I use a combination of a Garmin Montana device, Gaia GPS app, and Google maps to navigate.
PS: If you're following a track someone made, keep the following in mind:
The roads/trails might no longer be there, may be closed, might be private property, etc... so you may have to figure out a way around.
The terrain might be beyond your skill level.
The track might not run you through towns, so you'll want to be mindful of fuel.
PPS: You can use Satellite view on Google maps, Gaia, or similar to get an idea of what the road or trail actually looks like as far as surface. Just because it's a road on Google maps, doesn't mean it's not just an impassable rocky creek bed.
Weather. Be aware of the weather forecast, especially in the mountains. As a "flatlander" this has bit me many times while living in California. It can be sunny and 70 degrees when you leave, but 35 and snowing once up in the mountains. Equally, if it looks like storms are rolling in and you're in flash flood territory, it might be good to get to a major paved road ASAP.
Fitness and riding ability. Related to rule #1 in the section above, when riding solo it's pretty critical to be aware of the limits of your body and machine. Adventure riding solo is probably not the best time to test those limits.
First aid. Especially trauma stuff and the knowledge of how to use it.
Tools and knowledge of your machine. It's a good idea to know how to at least do the minimum maintenance and troubleshooting on your bike and bring the tools/supplies to do these things with you on your travels. The Dirtbike trail ride packing list covers some of this in more detail.
Download the owners manual and repair manual if you can get it to your phone. Even if you're a complete newbie, most of those will have step by step instructions on how to do things... with pictures!
Fuel. Make sure you know the realistic range of your bike as the fuel gauges on most bikes are very inaccurate. I know my bike can do about 200 miles and typically reset my trip ODO every time I fill up, so at 100 miles I know I'm about 1/2 through the tank.
If you bike needs premium fuel, keep in mind that it might not be available in smaller towns. It's not a bad idea of carry some octane booster with you.
Don't carry fuel (or any fluid aside from water for that matter) in your luggage. You can get bottle holders and strap them to the outside of your stuff.
Gatorade bottles work well for carrying fuel in a pinch, though I'm pretty sure it's illegal in the US and definitely don't put those in your luggage.
Food/water. If going anywhere reasonably remote always carry enough gear, food, and water with you to comfortably stay overnight. Water is especially important, especially in the summer, and especially in the deserts. I always carry 3-4L of spare water in one of the panniers (in an MSR Dromo bag, works great), in addition to whatever I have in my hydration pack. If I don't need it, my bike might.
Support services. AAA membership, or similar that will tow your bike if you have an issue you can't fix on the side of the road. AAA Premier RV is the one that has motorcycle coverage and will tow up to 100 miles. Your insurance or bike manufacturer might offer roadside assistance as well.
A plan if things go wrong. Having a emergency plan, even just in your head, is very helpful. This has to be a realistic plan that you can realistically do. For example, if the engine in my bike seizes, I'm not rebuilding it on the side of the road. I'm calling AAA, which is taking me to a hotel in a town, where I'm getting a Uhaul truck and driving my bike back home.
Support person. Someone at "home" who you can call if needed (from your inReach if needed). They should have copies of all your important documents and be briefed on what to do. I take pictures of pretty much everything in my wallet (drivers license, health/moto insurance, credit cards...etc) and put them into a shared/secure location online, with a couple family members having access.
Backup stuff. Definitely have a spare key for your bike. It's also not a bad idea to make some copies of your important documents (drivers license/ID, health insurance, bike paperwork...etc) and stash those copies along with some spare cash somewhere on the bike in case you loose your wallet.
Don't over-prepare or over-plan. The first time you pack your bike it will be a mess. The first few days will be stressful. That's normal, don't worry about it, it usually takes me 2-3 days to really settle into a trip.
This list may be helpful when it comes to specifics of what to carry with you - Dirtbike trail ride packing list
A few tips on what to do if something goes wrong - maybe you got stuck, or tipped over, or the bike broke:
Stop... Before you make it worse. This is especially applicable to being stuck.
Chill for a few minutes. Take your helmet off, take a seat, have a snack, look around, enjoy the nice forest or field you're in for a bit. Chances are you're probably going to be there for a while anyway, so don't rush. Unless it's a time critical emergency, don't start doing anything until your heart rate and adrenaline returned to normal.
Make a plan. Think through the situation carefully before doing anything. Maybe do some googling if you have service and aren't sure what to do.