Schlitterbahn

go to NB. Historically (like over the 35 years or so we have gone) we have always gone on Tues or Wed to try to beat the crowds. I would think Labor Day is a world class beating with the heat and crowds, but as long as you are there early before they open and secure a table in the shade, you'll be fine. Just bring your patience, sunscreen, and some kind of water shoes.

Passed by last weekend on way to Moody Gardens and lines waiting for it to open were long

We stayed in the cabins on the property. They were decent but not loaded with amenities. The best part is you get the park to overnight guests for an hour or so in the morning and 2-3 hours at night. Not everything is open both sessions but between the two times lots of stuff is available. It sort of allowed us to zig when the crowd was zagging.