Do you have an inverter and batteries; the good deep-cycle types? What kind of RV are we talking about - does is have room for permanent mounting of a generator, or will you need to set it up whenever you need it? A typical generator will be able to provide a surge rating of at least 25% over its' full rated output, maybe more, for the few seconds it takes to start the a/c. You don't need to buy a genset rated at 4000 watts just because the a/c start-up is quite high, but you may want to get one larger than your minimum requirements so you have some 'room to grow' in terms of power usage. Depending on where you stay, noise may or may not be a problem and, if it is, it can be a big one. Many parks and campgrounds have quiet hours when running ANY generator is a no-no. Other places are more lenient, but if you are running a 'contractor-type' generator (as we like to call them), you're neighbors may not be happy with you at any hour and may not hesitate to tell you so. Think of a generator as an investment; not an expense. It can provide you with many enjoyable hours of coolness and entertainment and talking with new friends. A loud generator, on the other hand, may be cheap to buy, but you may find yourself wishing you had put that money towards a good generator in the first place. There's not much of a market for used generators, especially those you buy on sale at your local building supply store.
