and it is much less crowded than the big parks. Spend some time in Capital Reef...There are a lot a great hikes there. If you want to fish, Lower Bowns reservoir is pretty accessible and just off highway 12 between Boulder and CRNP. If you have kids that like to fish, stop at the Garkane Power Plant pond just north of Boulder off hwy 12. Calf Creek also has fish and is a beautiful stream if you like to fly fish.
The leaves are changing on Boulder Mtn/Fishlake/Thousand Lake mountains so driving any of those highways/loops will be prime.