Morris County is the home of the Frelinghuysen Arboretum which is very active in native plant education. Try this web site for the native plant society. www.npsnj.org

Xanthorrhiza simplicissima (Yellowroot) does well in shade and it's rhizomes are good erosion control.

Catskill Native Nursery's website might be helpful to you. Conditions there are very similar.

Mass plantings of ferns or hostas could look great. If you naturally have ferns, consider yourself lucky--you could also do moss.

Not positive, but I think astilbes are native and they are very colorful.

How bad is your deer problem?