Why not just rent a cheap apartment and save up a good downpayment until you buy something you want? And when you say RV do you actually mean an RV or a modular home? A decent RV starts at like 100k and will only depreciate and you will have to pay for lo rental on top of that (assuming you don't plan on becoming one of those weirdos that parks in various mall parking lots for the night)

And how can a 3 bedroom home cost $1500 a month to rent? You must live in an insanely nice neighborhood. I charge the same price for my 5 bedroom house with a nice yard in a town that's been experiencing a heavy real estate boom for the past 3 years. Like Lukie says, maybe look for a more reasonable neighborhood.

Whatever the case, I don't think an RV is the way to go.