I've been over Boulder Mtn several times and here are a couple of ideas:
Hell's Backbone Rd: Easy for most cars, takes you thru some beautiful back country. This starts in either Escalante or on the North end of the "Hog's Back". Check with the BLM in Escalante about road conditions.
There appear to be many roads that lead back toward different lakes. Some of them may only be suitable for ATVs. We have friends in Escalante that tell me even my HC Jeep is not suitable for some of the roads on Boulder Mtn.
I'm not sure about coming off Boulder Mtn to the Water Pocket Fold, there is one road that's caught my interest but I've not done it, yet.
The Aspens should be great up on Boulder Mtn, we were there the last week of Sept last year.
Have fun,
Win