ASW 15 and concerns

Hello all,
Possible purchase of ASW 15....Tomorrow!
Done all the research I could, but here are a couple last minute
things.
I had someone reccommend doing a "TAP TEST" on the structure to listen
for inconsistant sounds indicating problems within. Esp. in regard to
the balsa core and the wood construction? I know all about the spar
rot thing, but what about the rest of the plane?

Also, my glider would be trailer stored, outside in humid Florida. It
only has passive ventilation. Any suggestions. I worry about the
suseptability to moisure?
Any input appreciated.
Thanks
Craig