Just remember that you will be 'putting' money into an RV, and 'investing' money into a house. Will you also need a car along with the RV, for groceries/errands after you get set up at the CG?
What if the RV has to go to the garage for a big repair? Where will you stay-a motel? Is your family covered for health insurance?
In other words: I don't think your idea will be as money conserving as you think. IMHO. I would find a place that you could afford, and save for a small PUP,(tent trailer) to see if your family likes RVing before FTing,. It's not for everyone.