Hi Big Jimmy,
Not sure how much I can help, but it would good to know a few things like...
What region of the country are you in (i.e. expected weather)?
Why do you want to cover it? Protect it from sun, snow, blowing debris?
Are you thinking about a soft cover stretched over the RV or a roofed structure to park it under?
Are you subject to any HOA restrictions?
The fact that you were told "...if neighbors complain it has to come down" would be a cause for alarm for me. Any structure which will be solid enough to withstand wind and possibly snow loads, will probably be pretty substantial and therefore expensive. Putting up something cheap which could collapse on top of your RV could possibly cause more damage than whatever you're trying to protect it from.
If the building inspector gives you a permit to construct it, would the neighbors be able to do anything at that point? I would think you could only get the permit for structures which are in accordance with local building regulations, so how could the neighbors protest at that point?
I'm not sure that helps you any, but good luck. :)
~Rick