The Technical Preservation Services office here at the Park Service
has been working on this for a long time. I'm pretty sure they have
one or more Preservation Briefs with guidelines and examples. I'm
think they work with people planning adaptive reuse projects for
historic buildings that include ramps, etc., too. The head of that
office is Sharon Park and I think she is also the one with the most
experience on accessibility, but I'm not sure about that.
I think she can be reached on e-mail at <[log in to unmask]> unless
she uses a middle initial, which I don't think she does. You can also
get a hold of her by phone at (202) 343-9584. If you can't get
through to her directly, see if you can get a secretary and ask who
can answer questions about accessibility.
Marilyn Harper