Hi,
Most generators in the 5,000 watt and above ratings have a 4 wire receptacle on them with the proper 120/240 power to them, and can be adapted to your 50 amp receptacle. You will need a twist lock 30 amp 120/240 plug and a 50 amp stove end (type used on RV's). You can also buy a 12" long 'Pigtail' from Camping World and other RV suppliers, sometimes with the 30 amp plug already attached, or you can buy one at Home Depot to attach it yourself. The friendly people at Home Depot can show you how it gets hooked up, or ask here.
30 amps at 120/240 volts is around 7,000 watts, and that is more than your RV needs to consume. It would be able to run two air conditioners, microwave, and other things all at once.
What most people are looking for is the lightest possible generator to run one or two air conditioners. What is your 'need'? If you only need to run one air conditioner, microwave, coffee maker, and perhaps a toaster, you can run 2 of these 4 items at once with a pair of Honda 2000 watt 47 pound generators hooked together!
Mayberrys.comCall and explain what you want to do. They have heard of a RV before, and can set you up with the correct cord and adapter for your 50 amp service if you don't have one already. You would adapt the 50 amps on your RV to 30 amps, then plug that into the power cord on the 'master' generator, and plug the two generators together into each other, so that the 'master' generator will decide what speed to run both generators, and they will work at the same frequency.
If you feel the need to run two A/C units at one time, you can get a 6,500 watt generator and run it, but the weight will be over 150 pounds.
Have fun camping!
Fred.