Caveman,
While I have most of the Rockies covered with DeLorme Atlases for CO, UT, WY, MT, and ID, I have gradually gone over to Benchmark Road and Recreation Atlases and I have come to prefer them to the DeLorme's. I carry both along on any trip, plus a compass, binoculars, and a GPS. I rely on the maps for "big picture" route planning, the binocs for checking out distant topo features to confirm location, and the GPS as a backup.
While I much prefer MT tires, the Western guys like Stew orient more towards cut resistance than mudder capability, and for good reason. Chopping up tires on sharp rocks has to get old, and fast.
Equipment/gear for a Wandering from Mexico to Canada? Wow, pretty much anything a guy can think of and fit into the truck, I'd guess. Just a few items off the top of my head would be: recovery gear, including a deadman anchor, tree-saver straps, a high-capacity come-along, snatch blocks, and both a short-handled and a long-handeled spade shovel; a 100% duty cycle air compressor; plugging kit with lotsa plugs and patches; radiator hoses and coolant; couple of fuel filters; perhaps a second spare tire if you've got room; big bow saw; long-handled axe; hatchet, splitting maul (to use as a sledgehammer and a firewood-splitter; small chain saw; fire extinguisher or two (of the type for extinguishing truck fuel/plastics, etc); first aid kit. I'm sure others could come up with many more ideas, just as they might suggest some of what I've listed is unnecessary.
And yes, welcome to WTW.
A few words about my own experiences with Western roads/trails: With the large exception of high mountain passes, the great majority of "off-road" travel you're likely to do will be on Forest Service roads, county roads, and BLM roads. Most will be graded gravel and while they get washboarded between gradings, they offer good driving. Since the US Forest Service and the BLM personnel generally drive fullsize 4WD pickups, most roads/trails which are of the major through-route character will accomodate your Ram.
Foy