Alan L:
You need to play the earlier Engh designs such as Redlands Mesa then Lakota Canyon to get a fuller appreciation of what Engh did in his earliest efforts and how they have evolved since then. Fossil Trace is well done given the limited amount of acreage but it's more of second tier layout in his overall portfolio.
Alan, I'm not a big time fan of Engh's work at Sanctuary. It's not that he should not be given substanial credit in delivering a rather different design on a site that nearly all had advised could not have an 18-hole layout of quality. Sanctuary does have its moments -- heck, the first hole from the "rattlesnake" tees is probably the best dropshot tee shot from a non-par-3 hole I have ever played. The ball hangs in the air long enough for any man to shave himself !
There's a few other holes of note but it's more a feat of beating the forces of gravity than a design that works well in a collective sense.
I can't comment about Colorado GC because it's one of the few elite courses in The Centennial State that I have not played thus far.
Yes, I have played Grandote Peaks in La Veta but it's a mixed review. My first round there was shortly after the course opened and it was fine back then. On a subsequent visit it was much less so because of management issues tied to turf care and overall involvement with the facility.
I like the layout but much of Colorado golf has long since passed the course in terms of designs of distinction.
I failed to mention Grandote Peaks before. Definitely worth a detour to see as well.
Alan, one other sleeper to put on your list if you have not already played it -- Bear Dance in Larkspur. Could be the most challenging and most picturesque of all the public courses in the state.
By the way be sure to schedule a round at Four Mile Ranch in Canon City -- you won't be disappointed.
Andy:
Harmony is well worth checking out. Engh did a solid job there and speaking of the greater Fort Collins area -- Highland Meadows is also worth a peak. Good effort from Art Schaupeter who used to work with Keith Foster.
Gents:
Can't say this enough but Colorado is soooooo deep on the public course scene. And you also get a healthy intersection of all the key modern architects there.