There is no economic justification, period. RVing, particularly in a class A motorhome, is not a way to save money.
The 25-30k budget is tough. But do-able.
Your 10 year old will be MUCH more comfortable in a motorhome than a truck.
Look for a good brand. Winnebago/Itasca, Fleetwood, newmar, and Monaco all made great 36 footish gassers.
Chassis doesn't matter. Workhorse or F53, in the years you'll be looking at, no difference.
Slides are good. More slides are better.
I see a 2002-2004 Fleetwood Pace Arrow with 2 slides (or something similar) in your future.
