I would say call RL first.
After that, try Ray Marchini at Cougar Country Outfitters 719-534-9016. No website, no marketing. He books full each year simply by word of mouth and can cater to your request for a truck (no atvs) and minimal walking.
After that, try Donny Carr with Golden Eagle Outfitters. http://www.goldeneagleoutfitters.com/
Donny is a great guy with good success.
If you are after trophy Colorado Mule Deer bucks, you don't need to be in shape as much as your check book needs to be in superb condition, if you know what I mean. There is no such thing as an "affordable" guided mule deer hunt out west.