I grew up in Lubbock and pass by the Carriage (House) Inn when I visit.
It is an industrial part of the city. The poster who stated about a 10 mile radius is correct in my estimation. At that time of night, he would be able to drive about 10-12 miles before turning around.
However, that doesn't leave much time for indecision. If he disposed of a body, IMO, he'd have to know exactly where to go.
This is one event where they should head STRAIGHT to the landfill and see what was dumped in the days after she was reported missing.
Lubbock has no storm drains. Everything drains into what are called playa lakes in local parks. Just west of the hotel are two of these drainage type lakes. There are a lot of these in Lubbock, but not many outside of Lubbock. They aren't that deep and if a body was disposed of there, it would need weighing down.
He might have been able to make it to Buffalo Springs Lake in that time, but again, he'd have to know a ravine to dump a body in.
Lubbock is very flat so a body would stand out on the surface.