I-10 straight through Houston is generally the best option, for those that want to avoid the city take TX105 from Beaumont to Brenham, then back down to I-10. It adds about 50 miles to the trip though. TX105 is a good highway overall, some 2 lane, some 4, though there is about 15 miles with heavy traffic around Conroe where it is 4-6 lanes wide. Like much of the Houston area Conroe is growing, and even TX105 is getting much busier than it was 10-15 years ago. As to the best time to take I-10 through Houston, that would be on a weekend, on Sunday mornings downtown Houston is a ghost town.
Make no mistake I-10 in Houston can be awful, see photo of the Katy Freeway section of I-10 on the west side of Houston below.
