Great questions SmokeyBear. With just about all pop up camper roof rack installs, whether Coleman camper racks, Fleetwood camper racks and others, you're looking at the same basic configuration. You'll need a pair of roof tracks attached to the fiberglass camper roof top and then you connect the roof rack system itself to the roof tracks.
As you mentioned, some campers come with tracks already installed and other do not. The distance between the tracks is roughly 76 inches - 78 inches or something close. What this means is normal roof rack cross bars are not long enough to span across this distance. Thule Racks makes a special extra long cross bar made specifically for this application. It is 96 inches long. So you'll want to use the Thule 430 Tracker II roof rack system with the 96 inch length bars as the cross bars choice. You'll also want to choose the TK1 Tracker Kit as the TK Tracker Kit component choice in this roof rack system. The TK1 Tracker Kit connect to the roof tracks and the 430 Tracker II Towers (also know as Feet) snap onto the TK1 Tracker Kits.
Now for those pop up campers that do not have roof tracks already installed, you'll simply need to get the Thule TB60 60" Tracks. They install onto the fiberglass roof top of the camper. The included instructions make the install very easy to do yourself.
You can then simply attach any gear carriers right to the cross bars and voila you are ready to haul all your gear on your next camping trip!
Thule LB96 96 inch super long cross bars
http://www.orsracksdirect.com/thule-lb96-96-inch-bars-popup-campers.html
Thule 430 Tracker II complete roof rack system
http://www.orsracksdirect.com/thule-tracker2-complete-roof-racks.html
Thule TB60 60 inch Roof Tracks
http://www.orsracksdirect.com/thule-truck-rack-tracks-60inch.html
Furthe info on questions about Coleman Fleetwood Pop Up Camper rack installs etc:
http://www.orsracksdirect.com/blog-fleetwood-coleman-popup-camper-rack-rec-88.html