I started the Divide Ride alone but frequently rode with others I met along the route for a few days or as much as a week at a time.

For a July 1st start I would recommend starting in Banff with a planned end point at I-70 in Colorado to facilitate your return trip home. You could always stop sooner at main points along the way if necessary or if you want a slower pace.

Without consulting the maps I guesstimate about 1500 miles of some of the most varied and scenic parts of the route including the national parks of Canada and the US. Daily mileage of ~50 miles per day. Elevations generally increase from North to South on that portion of the route allowing you to gradually acclimate along the way to Colorado.

I rode a rigid bike with front panniers only and a dry bag stuffer on the rear rack- a Bruce Gordon RNR with 700x47 tires with full fenders. This worked well for me but I traveled comfortably light in terms of equipment carried. Washboard roads and sandy or soft sections were more of a challenge for my tire width and volume but certainly doable. Any bike in your current stable of bikes will get you there on the Divide Ride- some with more comfort than others.