What is the best 100 miles of the Great Divide Route in Colorado?

[ghh@me.com]

My sons and I are going to do the entire Great divide route starting in Mid to late July.  I wanted to do a 2-3 day "shake-out" trip to make sure that all of our bikes/gear/Garmin trackers/left handed bacon stretchers/etc work properly before we head to Canada.  It turns out we can all 3 be in Colorado for 3 days June 1-3. 

So Im asking for advice on the what specific roughly 100 mile portion of the GReat Divide trail should we tackle to test out our legs/lungs/butts. 

Thanks in advance.