'classes' like this already happen.
30+ years ago i took a 1 credit hour class entitled the 'flora and fauna of florida'
we meet 1 hour each week to study the plants and critters and geography and geology of the panhandle state.
the instructor was a botanist and photographer for the national geographic.
then we all went camping for a week in florida,
to 'collect specimens' for the university natural history museum...
over spring break
many schools still have classes like this that include a week long field trip.
your proposal has some issues....
insurance will cover officially enrolled for credit university students
but 'non students' aren't included or covered, so it's hard to mix for credit with un-enrolled people
then there is the issue of 'too many instructors'
imo it's better to have 1-2 that cover the full palate than several.
there are liability issues for instructors as well.
it might be easier to sponsor this sort of 'class' at a 'communiversity' or adult learning annex...
many areas have these now and they regularly do these sorts of classes...
many larger universities now also offer non credit or degree programs for senior aged alums for free or very small fees...
just another option.
so it's a good idea rodney,
and many folks already do take these outdoor field trip classes on natural sciences, photography, social sciences, anthropology, archeology and related topics