And driving through the Rockies is nerve-wracking for a flatlander like myself...

I agree-- US roads are, for the most part great-- I was afraid of the rockies-- till i got there--The road (I-80) was so well graded-- i hit worse grades in the east! Going through the Delaware water gap was one of the "worst" stretches-- but at least i was familiar with the road (been through it more time than i can count-) and it was early in the trip--the first 4 hours of a 5 day trip.
There was some construction, and no medians, but in general, the rode was always 2 lanes in each direction, and 90% a median of 20 or more feet-- (over 6 meters).