We were snowbird RV'ers for over ten years and ended up with a Mobile Suites 38' with a custom built International toter that also had a barn behind the cab for a full dress Harley. That was to live in for at least 5 months at a time with our sticks and bricks being in Ontario, Canada.
Having said all of that the O/P in my mind would be wasting money to buy new and if needing a newer primary vehicle, would probably be best to consider something with a higher tow rating and multiple seating. The convenience of having a vehicle to drive while on site so you can explore and investigate fully the areas you visit is unquestionably his first priority.
Buying something like a receiver tow trailer in a length that has at least one slideout is probably the most cost efficient given his stated desires, the next option would be a lighter 36' fiver with a triple slideout giving him room for multiple beds. There are such a plethora of floor plans that finding a gently used unit should be easy enough. The crux of the matter with a family unit is when having guests staying they're not usually set up to have the younger members isolated from the guest sleeping area.
A fiver also basically restricts your primary vehicle to being a pick-up which also isn't the ideal for family cruising with 3 sitting in the back all the time.
There are so many manufacturers and floor plans, along with a toy hauler that can use the garage to double as a bedroom when needed.
Advice: Peruse manufacturers websites to glean current floorplans available then back track to used units. Join a few of the many RV'er websites such as "Escapees" and "5thwheelforums" to join their forums dedicated to RV travel and you'll learn a bucket load of useful info.
Lastly; do not make any snap decisions and get stuck into something that's going to cost you a bundle on maintenance to then 'double whammy kick' you by being almost impossible to sell later.
Your ideal set-up is out there, take your time and do your research of RV specific forums to avoid going too deeply into the jungle without leaving a trail of bread crumbs behind you.
Good luck.