Plenty of areas to explore within 8 hours just depends on what type of scenery you want to check out. If you like piney woods head north up highway 59 and once past Cleveland take almost any side road.
If you like hilly country Get on 290 till you hit Austin - longer ride but well worth it.
If you want to see the coast take I-45 south to Galveston then head west on the Seawall Boulevard till you come to Surfside (40 miles) then head Southwest till you hit Rockport.
If you want to see Indian Country get on I-10 and dont stop till you come to Ft Stockton - but that would be a 24 hour round trip but you would qualify for TX SS1000.
I am going to have a few free days in Houston TX the week of Jan 10. My wife will be in meetings all day and I will be free to explore a bit. I am thinking on renting a bike (only Harley's in Houston, as far as I can tell).
Anyway, does anyone know of any interesting roads or sights to see within an 8 hour round trip of Houston?
Any experience with the rental outfits down there?