Very minor point, but there was a reason I mentioned Russellville instead of Conway. The software that Buck and I use hasn't been updated yet to reflect that US-78 has been updated to Interstate standards, so you can get further than the computer on that day. To split the 3 days equally, Conway to Tucumcari would be a bit longer day than the first and last day. I also came up with far western Texas for the second night, but there really isn't much out there between Amarillo and Tucumcari.

If you go through Amarillo around dinnertime, you could stop at the Big Texan if you want a good steak dinner. If you want to spend the night there, the on-site motel is acceptable and reasonable, otherwise drive about a mile and a half farther west down the service road, there's an acceptable Motel 6 down there. If you do that, the 3rd day is going to be pretty long and you may want to think about stopping in Holbrook, the Motel 6 there is very reasonable and is the nicest Motel 6 I've ever stayed in. If you do take that 4th day, you could take the scenic route into Cornville - Alt-89 through Sedona.

I don't know if they still do it, but when I stayed at the Big Texan, they gave me a free voucher for breakfast at the restaurant - which is a full buffet with omelets to order. No wi-fi in the rooms, but the restaurant has free wi-fi - if you can get a room close enough on the 2nd floor you can pick it up.