Ok.. well, that changes everything. Sorry, when I hear someone say "S Post Oak", I immediately think "Galleria Area". You are WAY south of there.
From there? Frankly... Yea, I'd take SHT all the way North to the airport. It's not "traffic-free"...but, it's sure to be better than anything direct.
Here's the deal: If you PAY the tolls as you go, you'll pass ~ 4 toll booths at $1.75 each. IF you're on an expense account, most rental cars come with an EZ Pass system, that allows you to bypass the toll booths. They will send you a bill, about 2 weeks later.. that will probably be ~ $17. My company pays for them, so, I don't sweat them. But... if yours doesn't? Then, just pay the tolls as you go. They're not that bad.
When going from Webster to there.. DEFINITELY take the Beltway 8 toll road... It will be worth it. Likely only take you 30-40 minutes, maybe less. .. Not nearly as bad as where I thought you were going.
Houston's a fun place.. with LOTS of good food... try to enjoy it.
Thank you for the advice. I knew FR would come through. If you ever need help on the MS/AL coast, let me know.