Here is a couple of rides I've done:
-->Mount Herman Road up to Rampart Range road then take down to Woodland park then either follow 24 down hill to garden of the gods to santa fe trail back north to Monument
--->Mountan Herman Road up to Ranpart Range road then down to Woodland park then follow 77 to Sedlia and take 105 back to Monument.
Issue: Rampart Range is patrolled by forestry service and in Douglas County by sheriff. Lots of signs about "no off road unlicensed vehicles on Rampart Range Road". I've been very lucky and avoided the law but expect to get in trouble one day for not having a spark arrestor exhaust, no OHV tag, and unlicensed on licensed MV road.
I don't recommend taking Rampart Range road from Garden of Gods any distance..it is very busy with vehicles on weekends and more likely to run into the lawman
--> I haven't done this one yet and was supposed to last weekend but I had to have unscheduled surgery which ruled it out. Old Stage Road to Gold Camp road to cripple creek or take side trails that go up some of mountains in the areas.
--> another good ride could be front range trail in southern Colorado Springs up to AFA up to Monument then Mount Herman area circle back after hitting rampart range road taking single track back down to santa fe/front range trail.
If you do decide on riding any of these, nothing smaller than a 44 tooth and I strongly recommend a 48 tooth for single speed bikes-I have about half dozen of 48 tooth sprockets that I will give away for FREE to anyone in Denver/Springs area who wants one for the ride. If you use a tuned pipe like a SBP one, an extra 1.5-2 inches in header length will help with the low end torque assuming you are already tuned for higher engine rpms. I carry 3 lengths of copper 3/4 inch pipe to tweak my pipe for low, mid, and high end rpms. I'm usually tuned for low speed torque 99%of the time.
Extra fuel is a must. My Skyliner now has a rack mounted fuel tank in addition to the regular fuel tank up front and my Searcher has a rear rack with a bag that I store 1/2 gallon of premixed fuel in it along with tools for long rides.