We went banana boating on White Lake yesterday. Loads of fun, but you need to be ok with getting wet. (soaked actually).
Its $80 for 30 minutes, and up to 6 people fit on the raft. You will also need a person to ride in the speedboat to see if anyone fell off (and that ususaly means all riders). If you can’t find a speedboat rider, you can hire one on the dock for anouther $12.
Another good trip is kayaking down the Delaware (very tame), or tubing down the Esophus (very wild).
You can also check the NYNJ trails conference for hikes of every type and lenght. Ice Cave mtns just outside Ellenville has a small loop that can be done by almost anyone in less than 2 hours r/t, and a longer Waterfall loop which takes about 4 hours r/t.
There’s also the 6 hour ride back to the city, which is great for 1st year bonding!