Mike -
On the subject of school groups and seniors:
Keep in mind that working with school groups creates (some) museum-goers
for the future.  As far as decrease in funding - I've found that in New
England, at least, parents groups and even teachers will come up with the
money somehow if your programs are worthwhile.  We ran at a 60-75% profit
margin in Connecticut ( and we were definitely not on the must see list)
which any business person would tell you is good. (This depended on
well-trained volunteer docents.)
The seniors market is definitely worth pursuing.  Keep in mind that
programming should be fairly short in the museum and during the daytime.
We had our best luck with outreach programs to resthomes, etc.  We took
various aspects of our collections and created slide shows which
volunteers took out.  The personal touch was important, and many
volunteers who did not like working with children were interested in
working with seniors.  You will also find that your school slide programs
will work well with seniors!  We charged $25-30 per program plus mileage
outside a 10-mile radius and did quite while.  Most resthomes had
contracts where we came once a month.
Hope this is helpful.
Kathrine Walker, Beach Art Museum, KSU