I can't speak to your inquiry about Mt. Baru, as we didn't do that hike during our stay in Boquete.
I will though highly recommend the rafting trip on the Chiriqui river. The guides were well trained, the boats in good condition, and the staff in general (from office people to driver) really friendly and accommodating. I imagine the water levels change frequently, but when we went there was plenty of class 3 and 4 rapids to make for a very exciting trip. (4 overboard drills, but 3 of them the same guy so maybe user error was part of the problem. grin).
We used Boquete Outdoor Adventures. The owner, Jim, also arranges other trips. Fishing on the coast, kayaking at Boca Chica on a remote island (we did this too; very nice day), and I believe he arranges Baru hikes as well. He struck me as the kind of guy who would give you straight info. and tell you if he thought you weren't up for the hike, and not just drag you up there to get your money.
Enjoy! (And try the fish tacos and a margarita on the back deck of Big Daddy's while you're in Boquete! Freshest fish in town, and good people to hang out with.)
Jim, the owner, also arranges Baru hikes I believe.