Hi... converting a bus to non-poptop camper is trivial, hardest part is 
water drain and propane if you have it. Everything bolts in, nothing major 
different in clamps etc, but you will need ALL the little fitting 
pieces/clips/anchors. Bare cabinets alone are not sufficient. It helps if 
you dismantle the old Westy to understand what goes where. Pre '71 poptops 
that are small, 4' x 4' pop up straight with no hammock, are easy to fit, 
Email me direct if you have one. Full length conversions with luggage rack 
and hammock are likely lots of work, although I have seen a few, from the 
outside only. I would suggest only cutting an access area, 4' x 4' then 
putting on the full roof. No bed but everything else. Never cut the roof 
ribs!   tim s.