you won't have enough time for the museum.

The simplest thing to do is to go to the airport marriott. I've done it occassionally when waiting. It ain't the cheapest or the best, but it is convenient and is in fact the ideal place to wait if the party you're waiting for has a cellphone. (it's not at the terminal, but damn close to it and has parking).

there are some other choices, but the rest force you to leave the airport and drive back.