billberge,
The c2512 is an Access router. Comes with 1 token ring, 2x serial and 16x async ports.
If you want to put it on the LAN, then as you've stated, you'll need to connect the token ring interface to a token ring switch. Not sure if the cat2950 will support token ring though.
You can use the serial interface to simulate frame-relay. You'll need another router with serial ports so you can connect them back-to-back. The async ports are used for dial-in access (the primary purpose of access routers), or you can use them to reverse telnet into other cisco devices. The c2512 is a great router to add to your lab, but perhaps not as the first router in your lab when starting out learning. It would be better to get a router with an ethernet interface which could easily connect to your switch. The 2512 could then be used as a secondary router for frame-relay and reverse telnet.
JimmyZ