There are cabins at Linn Run state park, maybe you will get lucky with a cancellation, but here is a link for the trails.

https://www.dcnr.pa.gov/StateParks/FindAPark/LinnRunStatePark/Pages/default.aspx

Or check out Donegal or Somerset. 7 Springs ski resort is located there, but there are cabins and air bnb’s around. Polymath Park is a group of Frank Lloyd Wright houses- I am certain they will be booked (and expensive)- but it is an easy drive over to explore for next time. They are close to Falling Water. The mountains are beautiful now, and if you like a chill in the air when it warms up in the afternoon, now is the time.