Something I find really useful for my Five Wide trips is the Jackery rechargeable power supply. You can charge it from another generator, the car, their solar set-up, and from AC. I have the 500. They have various sizes, and now there is a 1000. No gasoline involved and no noise.
Great for recharging phones, camera batteries, running my 12 volt blanket, etc. A regular electric blanket would run it down in a hurry, but my 12 volt blanket shuts off in 30 minutes. A heater would run it down pretty quickly also. I'd love a 1000, but the 500 is a good size for where I have it sitting. The solar would be nice, but I live around too much shade, and the Jackery solar is not waterproof.
One can also get cables to recharge your car or trailer battery. It is not a jumper, but recharges in a fairly short time. I have not tried that yet.