With Priceline, you can now bid up to 11 PM EST for a hotel that night. So if you have Internet access along the way, I'd bid 2.5* when you are in the approximate area you want to stop. (I'd be okay with 2*, most likely, but I suppose, there's the possibility these could be dodgy.) I believe Hotwire can be booked by phone: 1-866-HOTWIRE

Otherwise, in my limited experience roadtripping pre-Priceline, I thought Best Westerns were pretty good, but I suppose there are exceptions.