Sounds like my kind of trip. I went to the East coast from CO by way of the smallest roads I could find. I had to cheat and get on a freeway to get from Manassas, VA to Danbury, CT on my way to Maine, but that's only because I really, really didn't want to be downtown New Jersey. 
If you haven't ridden through SW CO yet, then I'd suggest a little more southern route back. Hit the red rock area of AZ (Prescott/Sedona), then up to Grand Canyon. Then go through the 4-corners to Durango, CO. Monument valley (north of Kayenta AZ) is also cool, but you might have seen this on your way west depending on how far south you went in Utah. Take 550 north from Durango to Montrose and then east on 50 if you're in a hurry...
If you have time to spare, ride the north rim of the Black Canyon near Montrose or head a little further north to Aspen and go over Independence Pass. ...or Hwy 141, or anything in that area. It's all good.
My favorite off-freeway route from the mountains through KS is Hwy 24. You'll need to find an alternate path from Limon, CO to Colby KS, and there's not much out there. It's not as populated as 36 so finding gas and food might not be easy.... but at Colby you can go straight East on 24 and it's about the most interesting bit of KS I've found so far.
If you haven't ridden through SW CO yet, then I'd suggest a little more southern route back. Hit the red rock area of AZ (Prescott/Sedona), then up to Grand Canyon. Then go through the 4-corners to Durango, CO. Monument valley (north of Kayenta AZ) is also cool, but you might have seen this on your way west depending on how far south you went in Utah. Take 550 north from Durango to Montrose and then east on 50 if you're in a hurry...
If you have time to spare, ride the north rim of the Black Canyon near Montrose or head a little further north to Aspen and go over Independence Pass. ...or Hwy 141, or anything in that area. It's all good.
My favorite off-freeway route from the mountains through KS is Hwy 24. You'll need to find an alternate path from Limon, CO to Colby KS, and there's not much out there. It's not as populated as 36 so finding gas and food might not be easy.... but at Colby you can go straight East on 24 and it's about the most interesting bit of KS I've found so far.