If I had to commute from Sugar Land to Downtown everyday, I'd:
1. Suck it up and pay the HOV/HOT tolls; or
2. Buy a cushy 60+ MPG scooter that can hit 80 MPH, stash some rain gear in it, and cruise the HOV free every day. Super easy ride straight to/from downtown, or
3. Pick up a slug from a Smith Street bus stop, ride HOV to West Belfort Transit Center, drop them off, continue solo on 59 (traffic flows freely after Beltway 8 until 99 mess).
I'm assuming #3 is possible. Never done it. I do know a Texas Ex chick who use to do something similar years ago to get on the Katy Freeway HOV. She kept a small sign in her car. Picked up people from bus stop. She says she never had a problem finding riders. Now she lives in a new Bellaire mansion, so it's not an issue.
All that being said, at the hours OP is talking about, traffic is rarely an issue. Being close to the freeway is a big help. Some suburb locations are a beating just to get to the freeway. Avoid that at all costs.
Bernard