After Landing

At this point I'm rolling down the runway at 40 miles per hour. I could just turn off the runway after I got slowed down but generally the tower controller will tell me which turn off to use. Sometimes they will ask me where I'm parking and that will help in directing me to a convenient place to turn off. In this situation the controller probably knows I want off to the right but doesn't tell me what frequency to change to to contact ground as he knows I already know it. Of course the frequency is listed in the facilities directory so anyone landing should know what it is. So I taxi off the runway at :Charlie Four" and change my radio ro 121.7. There are lines on the pavement I need to cross to be officially off the runway and I need to be beyond this makring before I stop and change to the ground frequency.