We didn't have an opportunity to try any of the outdoor activities in Jim Thorpe but it seemed like there was a lot to do. We saw rafters and kayakers on the Lehigh River and saw lots of people biking and hiking along the riverside trail.
From the attached website it looks like rafting season is from mid-March to October with the best rapids (class II and III) in the spring, the summer time is more tame.
We saw some bikers that had just finished the 25 mile trip through the Lehigh Gorge State Park and they asked me to take their picture to commemorate their accomplishment. I laughed at first because 25 miles on the flat terrain in Illinois doesn't seem like all that much but I reconsidered after looking at the surrounding hills. :-)
Just across the river from the historic center of Jim Thorpe is the Glen Onoko access point to the Lehigh Gorge State Park.
There's a trail that follows the Glen Onoko waterfall all the way up the mountainside.
In places the trail is well marked, but as you approach the top it gets a bit rough - be prepared.
Equipment: Good hiking boots would be helpful.