Philly is great for riding and it is really big here. I know there is definitely a dirt scene here but I can only comment on the road experience. There are a bunch of great group rides everyday of the week once daylight comes back in our favor. Here is a link to the most popular ones: Area Rides - QCW Cycling
They all start in the city and are easy to get to from Penn.
The roads are safe and the city has a lot of bike lines. Roads outside the city are safe too and that’s where you would find the hilly stuff and the better riding. For dirt stuff, I know Wissahickon has great MTB trails but I am sure there are others. The Schuylkill River Trail is a paved trail that starts in the city and follows the river to beyond Reading (About the Trail - Schuylkill River Greenways). It’s pretty wide and smooth so it’s a frequent route for a lot of riders for training and getting to Valley Forge Park.
There are crits and races within an hour and half drive on both days of the weekend during the season. It’s also not a rare occurrence that there is a race within riding distance. Philly has a bunch of teams and all have cats 1-5. Here are a few:
- QCW: Our Club - QCW Cycling
- CS Velo: https://www.csvelo.com/
- Tristate Velo