Morris is played by the real life Sam, Rich's friend from college. And the actor playing the radio interviewer is Rich's real life younger brother David,
The girlfriend is actually a compliation of a couple of different girl's in Rich's life.
In the movie, Rich's dad mentions Rich getting all four wheels of a tractor stuck in holes. Rich's brother in the commentary says this is based on a real incident, but it was a car, not a tractor.
The house Rich bought in the movie and threw the "for sale" sign, was the actual house Rich had bought in Tennessee. While the "for sale" sign was up for filming, neighbors kept calling the current owner fearing she was moving.
Rich's brother Dave appeared in the movie as the DJ and Dave's daughter played Rich's sister and Dave's son played the teenage Rich.