Your camping trailer already has a back bumper. You can modify the bumper to create a small platform, on which you can attach your generator and other supplies. Buy a length of metal, plastic, or wood material and attach it beneath the bumper of your trailer. It should not stick out more than a foot or two, and should not ride any lower than the bumper. Attach it with screws and make sure that it is also attached to the undercarriage of your trailer so that it does not pull the bumper off. Place your generator on this platform, cover it with a tarp, and tie it down with bungee cords. You can use the rest of the platform to attach bicycles, closed tubs of supplies, or anything else you need to take along. Be sure that you attach a red or brightly colored piece of fabric to the end of the platform, so that drivers behind you are aware that the trailer sticks out further than it looks like it will.
Keep in mind that anything attached to the trailer in this way has the potential of being stolen while you aren't watching, or when you are stopped somewhere. You won't be able to see it from your car as you pull the trailer, so you will be taking a chance by attaching it in this method.
Your trailer should be attached to your car or pickup by a hitch. Around the hitch, you might have as much as 6 inches or perhaps a foot of space. Create a platform in the same way by attaching a piece of metal or plastic to the hitch and to the front bumper, and tying your generator down to it. Keep in mind that depending on the specific alignment of your trailer, this might not work. Also, keep in mind that if the generator is not securely attached to this area, it could fall and cause an accident. It will be harder to back up your trailer and perhaps more difficult to turn if the shelf is too big and sticks out too far, so keep this in mind while you build it.
Tie a generator to the roof of your trailer. This can be used for long-distance travel, as it does not allow you to have easy access to the generator without pulling it down and setting it up, or climbing to the roof. When you tie a generator to the top of your camping trailer, be sure that it will still clear bridges and other places in need of clearance.
