Thanks everybody.

, read the two responses which precede my "any
useful responses?". It isn't like people gave me a real answer and I
decided it was stupid. As for the google search on it, I've already
done it, and found a lot of the usual non-comittal jargon about how
safe it is or isn't.

I'm leaning towards replacing everything but the foundation frame with
untreated wood, but would still appreciate it if anyone had helpful
information.