You'll encounter some smaller (relatively) hills between Mesa Verde and Pagosa Springs. The big climb is over Wolf Creek Pass (10,856'). About eight miles up a good steady 6 - 7% grade to the summit but it's two lanes uphill so stay to the right and just take it slow. Stop at the summit for the view and to let things cool down.
Of course watch your speed on the east side downhill run. Downshift for engine braking, don't ride your brakes, and pull over if you find you're backing up traffic. After the second tunnel the downhill grade is less but the road is narrower, there's no shoulder to speak of, and your attention is going to be drawn to the beautiful view of the river next to the road.
Once in South Fork things pretty much level out across the San Luis valley to the Sand Dunes. If you need supplies (food/fuel) stock up in Alamosa because there ain't nothing closer.
If you're continuing east after Sand Dunes you'll have to cross La Veta Pass (9,400'). Also two lane uphill so again slow and steady.
BTW, you said "so trying to gauge the lesser of what appears to be two evils". What's the other choice? Short of detouring into New Mexico Hwy 160 is really the only option.
Barry, MSgt, USAF, Ret. & Rose
2015 Nissan Frontier V6
2014 Coachmen Viking 17FQ