If the setup’s only going to be for occasional campouts….
You might just think about getting a small Bus and tow a small travel trailer behind it.
That system would give you a place for your kids to hangout …plus you’d have a small rig that’s a lot easier to drive around narrow streets than a big Schoolie is.
You could set the small bus up with a simple kitchen & bathroom …and the trailer could contain the sleeping arrangements.
Say you get a bus like Firearm has…
He has a little over 10-1/2 feet of useable building space inside…then you buy a used 16-18 foot trailer (which will have around 12-1/2 –15-1/2 feet of interior space).
Now you’ve got approx. 23-26 feet of building/living space.
That’s a good bit of space for camping out…(My ‘big’ 66 passenger bus has only 27 feet of useable interior)
If you bought a used trailer (lots of little trailers for sale for very little out there)…you’d have all the RV stuff you could pull out and install in the bus …then you could set the trailer up with bunk beds or whatever.
If you like building stuff …and would rather make your own trailer instead of buying one , here’s a good forum to check out. They mostly build the little Teardrop trailers …but there are a few folks over there that build larger setups.
Michael & Millie