You can drive the clockwise direction from Questa around to Taos in about an hour if you just want to see the pretty scenery and not stop. There are two mountain passes-one outside Red River and the other outside Angel Fire. Neither are steep but both have slower curves.
Fuel up before leaving Taos.
Food stops in Red River, Eagle Nest and Angel Fire.
If you're tired, go back the way you came and don't worry about the drive until your next visit as you say.
Depending on how late in September, there may already be some snow on the peaks above the drive route. Pretty. You'll be able to see Wheeler Peak just down from the pass outside Red River and then through most of the Moreno Valley between Eagle Nest and Angel Fire.
The Vietnam Veterans Memorial outside Angel Fire is really special.
Daylight will last well after 6 pm that time of year, so you won't need to worry about driving in the dark if you're done with the llama trek by 3:30.