You don't have a bus yet, right?
Maybe, shop for a longer bus. Our skoolie is 42'2". Add a rack to the bumper and I max out at 45 feet.
You might consider pulling a trailer behind your conversion. Either RV living space or enclosed storage. Some members here have added slide outs to the rear and sides.
We already had a shipping container and an rv when we added a school bus to our yard. I recommend having onsite storage and restroom facilities before you begin your conversion.
"A man is worked upon by what he works on. He may carve out his circumstances, but his circumstances will carve him out as well."