Reading between the lines... I take it you are planning a 3-5 month trip for next summer seeing some sites on the way to CO and then after exploring CO, finding a spot for several months until you go back to Fla for the winter. I would not worry about cell service as a tower on a high spot (Fla does not have any) provides a large area of coverage.
I would suggest joining Passport America and start in the CO Springs (several PA CGs) area as a base camp and explore the area as day trips Next I'd move to South Fork (one PA) and do day trips, even as far as Lake City in the car. We like to boondock in USFS CG during the week (less crowds and plenty of spaces for a big rig) and then resupply and re position on the weekends when the locals go to the woods. From there I would take 160 to the Pagosa Springs/Vallecito Lake (one each PA) area for the next week. Next I would go to the Silverton/Ouray area but no PA. Next I would head to 50 and the Gunnison area (2 PA). We like Taylor Park but cell service might be a problem. From there I would head to the Breckenridge/Silverton (9 and I-70) which will be your most expensive area. Next 9 north to the Kremmling area and then east on 40 to Grand Lake for RMNP. Then back south and towards the Denver area or to one of the previous areas that you liked best.
The beauty of a big rig is how well you can go without hookups for 5-7 days without cutting back on anything. All of the areas above should not need AC. Granted you will have to run your generator 1.5 hours at night and 1 hour in the morning... partly to recharge the batteries that power your home refer while boondocking.
