Laryn's trip planning out here to the West Coast, and the various comments that have been made about routing and highways, has prompted this industry veteran to make the following suggestion:
When planning a trip, if you're unsure about the highways in a specific area, try contacting a local charter bus outfit. Ask them if they run charters and/or tours into that area, and what their recommendations are for routing. (Ask to speak to an Operations Supervisor, not the Sales Dept!)
Think about it - if the local charter bus outfits are in/out of the area frequently, a busnut shouldn't have any problems either.
All bets are off, however, if you're headed to "off the beaten path" stuff.
(BK & BW - Wouldn't you agree??)
FWIW & HTH. . .
;)
And if they don't go into a certain area, it is probably because it is not scenic or otherwise worthwhile.
JC