Doing some trip planing. The Good Sam Trip planner routed me from Grand Lakes CO onto HyWay 34 on my way to Minnosota in Aug. I have a 38 ft Class A with CAT 300 towing a Honda CR-V on dolly. ...
As far as I know - if you're going *from* Grand Lake to Estes, then there aren't a lot of options.
34 from Granby to Estes will run you through Rocky Mountain National Park (RMNP). And you'll be going up and over. There might be some switchbacks that'll give you pause, but the road is paved.