Mid-October to early November is prime fall color/minivan/RV season. If you go during that time it really isn't that bad except for on the BRP. You will need heated gear during that time also, it is cold in the mornings and at elevation. It is really beautiful if you catch it at the right time.
If you don't care about the colors then early October or before would be the time to go. You might see some good color that time of the year at elevation, it changes sooner.