Last week we were in SE PA for my husband's 50th high school reunion. On the way back to VT we did some sightseeing and I really enjoyed and recommend the following sites:

1. Grey Towers National Historic site. This is in Milford PA, just off of I-84 at the northern end of the Delaware Water Gap. We chanced upon the site two years ago when we were going past Milford and I thought it seemed like a good place to stop for our picnic lunch. We really enjoyed our brief time there and our quick tour of the grounds and decided to go back to tour the mansion.The property was owned by the Pinchot family (Gifford P was the first US forester and very influential in promoting natural resource preservation in the early 20th century; his wife was a prominent social activist.)Grey Towers is a lovely spot with beautiful views and the mansion is very interesting. The mansion will be closed soon for the season but the grounds are open year round.
https://www.greytowers.org/

2. Historic Huguenot Street in New Paltz NY on the western side of the Hudson River. This is another interesting historic site telling the story of the Hugeunot (French Protestant) families who settled in the area in the 1600's and of the Indian tribe and the enslaved people who lived in New Paltz.
https://www.huguenotstreet.org/
There are many other interesting places to see nearby in the Hudson Valley on both sides of the river.