I have never owned an RV and am contemplating going out full time with my wife and two teen aged kids. As much as I think a fifth wheel would possibly give us the most living space, I feel the cost of...
I would rent an RV for an extended trip at least two weeks with travel between several destinations to see how your family handles the confinement. Try to pick a time when you will hit inclement weather where you may be stuck inside for a few days and watch the cabin fever kick in.
For more fulltime info including month by month expense this is a good website to read through www.rv-dreams.com