PVT,

I don't ride so I can't really offer suggestions as to what sort of gear you may need in that sense, only to say I would plan on some chilly to cold days even at low elevation in the Northern Rockies.

As to mapping/planning, I would never, as a matter of personal choice, rely solely on any form of mapping software and smartphone/tablet/laptop hardware. Old-school folding maps are available, normally for free, from each state's DOT or tourism department, and ordering a set ahead of time gives you the opportunity to stash them in your saddlebags before you set sail. Getting a folding wall-size map of the US from, for example, the National Geographic Society is a good idea, too, as it will provide the big picture for general planning and a base for you to program more specific routes into whatever app you find will work for your smartphone or other hardware. The Rand-McNally series of US Highway atlases, updated annually, might also be employed, where you may choose to cut out pages of relevant states as well as the "entire Lower 48" map which is at the front of each year's atlas. If it were me, I'd just take the whole dang Atlas, but I'm accustomed to cross-country travel via car or full-size pickup truck where space/weight isn't much of a consideration.

Foy