The most convenient is a Holiday In Express that is located at the park entrance just north of Westheimer and west of Hwy 6.
That's where I stayed 2 weeks ago. Nice place but not the most economical, about $100/nite. Good breakfast bar.
There are others next door and just down the street in the $75 range. These less expensive options I don't recall seeing them when I made reservations on Priceline.com. Once you located HI Exp on Google Maps zoom in to see the others..