The good part of U.S.550 is south of Grand Junction so that would be a detour for you.
I-70 west of Denver from Breckenridge to Eagle Creek is amazing, you'll see what I mean.
Once in Utah you're going to be so damn close to Moab, worth the detour if you ask me, nothing else like it.
On the way back, come down through Utah and catch 89 in Logan, UT. Logan is a nice town but 89 from there up to Bear Lake is one hell of a road. From there you could drop back down 30 through Kemmerer to I-80 in Wyoming. Taken this route many times and love it...
or from Swan Valley you're just a few mins from the Grand Tetons, take 31 to 33 and over to 191 in Jackson, again the scenery is nothing short of amazing in the Tetons.