I've towed my Leaf on a dolly, no problem. Just make sure the parking brake is off.
It's not recommended to tow it in neutral with all four wheels on the ground, but I think it can be done without damage to the car with an apropiate tow bar setup. But that's just a thought, because Nissan does not recommend this for some reason. So I guess there's a possibility that it could mess up something. But if you did tow with all fours, there is the potential of shifting into D and using the engine of the RV to tow the Leaf an charge the Leaf at the same time via regenerative braking. I've always dreamed of making some sort of device that could control the Leaf's accelerator, shifter and brakes from the cab of the towing vehicle or have it automated along with the towing vehicle's controls. It would basically cause your Leaf to turn your RV into a hybrid. But maybe that's a far fetched idea.
Anyhow, back to reality, as far as charging I suggest the Zencar EVSE. It can be ordered with the apropiate amp levels for any outlet. 12A for a 15A outlet, 16A for a 20A outlet, 24A for a 30A outlet and 32A for a 40A outlet and will work on either 120V or 240V. All you'd need is to make some adapters. Of course that's assuming you have a 6.6kW Leaf and not a 3.3kW Leaf, in which case you won't be able to pull that many amps.
The generator has to be wired in a special way for most EVSE's to work. Basically combining hot and neutral to ground via a couple of resistors. A lot of people have also had problems charging with some cheap generators. But not that it can't be done with a good generator.
Another alternative is to plaster the whole top of your RV in solar panels and use and inverter to charge the Leaf. You might get enough to at least do some level 1 charging for four or more hours. (Even with cheaper solar cells you could do an 8' x 20' 2,000W solar array for around $600 for just the cells, solder, flux and ribbon wire, the frames and glass would be extra). That's not a lot of power, but if you could make those panels hinge and you keep pointing them towards the sun all day you could get 12 or more hours, enough for some 50% of charging. Make them double or triple up and hinge out to a 24' x 20' square and you'd get your full 6kW. A lot of work, but hey! it might be worth it to some people. Plus it would work as an awning on your RV. You just wouldn't have space for an A/C unit on top.