What specific protocols or guidelines should be followed when designing recovery rides on an indoor trainer, particularly in terms of intensity, duration, and cadence, to ensure a rider is not inadvertently pushing themselves too hard and undermining the recovery process? How do riders balance the need to maintain some level of cardiovascular fitness during recovery with the risk of overexertion, and what role do perceived exertion, heart rate, and power output play in this delicate balance? Are there any specific indoor trainer workouts or programs that are particularly well-suited for recovery rides, or is it more effective to simply freeride at a low intensity?