I am new to the skoolie.net and I am considering joining the skoolie asylum

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My wife and I are considering purchasing an alternate to what we have, dodge cummins 2500 with camper. Considering an alternate since we recently went over to the coast with the camper and my 5000# boat and the truck and camper had plenty of power but the camper causes a fair amount of sway even though I have had a rear sway bar installed, also the layout of the camper just sucks mainly because the amount of space that is available.
I have noticed a fair amount of school buses on craigslist and I am interested in the idea of a bus as an rv.
With that I have come up with some questions that I thought could be answered here?
What motor/trans would be preferred considering my needs? Cat, cummins??
Can the 40' buses be shortened, if so how difficult is it?
I noticed some discussion about governors, which motors are the easiest to deal with with that issue?
Thank you for any responses
Gary