I can't give any info as far as towing capacity but I do know there's many, many shuttle bus conversions out there. Including on this forum. Assuming the body is in good condition and not sun cracked, torn, etc. I imagine it could last a long time. There's lots of fiberglass on the road from the 80s still. Fiberglass poses its own set of problems but there's always a workaround.
-Travis & the DawgBüs
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