Home of The Wall...I began riding in '99 for fitness. Usual ride is from my office to Valley Forge and back (1-2x/wk). I stumbled upon Bike Forums in my search for info on choosing the right bike to replace my 10 year old rusty mountain bike. I am still confused and component info is gobbltygook, but some of the threads here have helped. I leaning toward a cyclocross...seems versatile and durable.
One of my favorite rides (haven't done it since last summer, though) is a big loop from my home in Ridley Park, up 252 through Ardmore, out to Valley Forge and through the park, then down the Schuylkill Trail into Center City, then home (the last leg is also my daily commuting route). It's a "metric century."
The Trail is fun because I don't normally ride on paths, so it's interesting to do some riding where there are more bikes and skaters and joggers and no cars. It's slower and more dangerous, but fun, and the scenery is nicer.
My office mate commutes to CC daily from Manayunk on a Trek hybrid I sold him. From the tales he tells, I'm just as glad there aren't any bike paths on my commute.
I'm sure you'll find the perfect bike, and this is a good place to come to for advice.
I have never ridden the "trail". I have been wondering what kind of shape the path is in. Is it pretty smooth, bumpy, or in between? Is it crowded all the way out to Valley Forge or just in toward Center City?
From VF you cross a bridge to the beginning of the bike path. From there almost to Manayunk it's a wide path, flat, paved, and in excellent condition. Where it's crossed by roads you'll need to slow down; there are barriers to rpevent cars from entering.
The Manayunk section includes a canal towpath that's gravel-covered. Then you go on-street for a mile or two to connect with the Fairmount Park section. From there to the Art Museum it's narrower and busier and crowded most of the time.
Personally, I plan any ride that includes multi-use paths (which is as few as possible) for weekdays to avoid the worst of the crowds, but the lower part of the path between the Art Museum and the Strawberry Mansion bridge seems to always be full of people intent on being in the way. Not recommended as a place to ride.