RE: Decent roadfood on I 90 West
I just made the trip last month, so have got a few suggestions. Not much healthy, I'm afraid. (Two kids with cravings for bacon cheeseburgers.) At least they are local places, not the chain of chains you find at every interchange east of the Mississippi.
Chamberlain, South Dakota. Casey's Drug Store and Cafe. Right off the highway. Pretty standard cafe fare, with good portions, good potatoes, so-so salad bar. They advertise the "perfect cheeseburger," though their authority is a 1976 article by a New York writer just passing through town.
Livingston, Montana. Clark's Crossing (westernmost I-90 exit) Buffalo Burgers (healthy, low-fat), waffle fries, and very good clam chowder, for some reason. Giant needlepoint map on the wall depicting Lewis and Clark's travels.
Molly's Restaurant in downtown Spokane, WA. Their motto is "you'll never leave hungry." I had a chef's slad that was quite good, very large, and even had lettuce beside iceburg in it.
If you get the chance to get off the highway in Missoula, there are several good places, most of which are hippie hold-overs. In fact, there is a store called the "Good Food Store" which started out as a hole-in-the-wall place in the 60's, and now occupies an entire shopping center. I believe it has an eat-in cafe, but if not you can stock up with enough fresh, organic food to last the rest of the trip. Take the Russell Street exit, go south to Third Street South, turn right, it's on the corner.
I may think of some more places later. When exactly are you leaving?