score:2
I've found reviews at Trip Advisor and, especially, Booking.com to be reliable. You can get mobile apps for both.
The idea of sticking to one chain is also reasonable, but it might be difficult in some of the less populated areas.
Off topic, on that route I recommend making a detour to as many National Parks of the Southwest as possible.
Upvote:6
How 'good' do you need it to be?
A room at any of the major hotel chains will be a clean, comfortable sleeping spot.
Smaller mom & pop places can be nice as well, I usually check their outside appearance first... clean parking lot, hanging plants, a bit of outside furniture.
Most small motels will let you see the room before paying.