Howdy,
Welcome to the site! Of course I can recommend some more routes
Come through Huntsville by way of FM 149 and Fm 1791 to Hwy 30. Leave Huntsville via FM 247 on the North side of town. Run this up to Midway on Hwy 21 just East of Madisonville. HIt the OSR Highway and head to FM 1119 and go North. All of the little FM's in the area between there and Buffalo are a lot of fun, particularly FM 1511. Right where FM 811 hits Hwy 7, there is a great little cafe, Pioneer Cafe. Good food, nice service and cheap prices. Both sides of FM 831 East and West of FM 1511 are fun but can be a little bumpy in places.
FM 977 heading West through Leona to FM 3 is a lot of fun. It has tons of great sweepers and beautiful scenery. I usually make my way back to Madisonville from Normangee. You can then come down US 75 which run basically parallel to I-45 back to Huntsville. Then backtrack FM 1791 and 149 to Montgomery. It is about a four hour loop from Huntsville and back if you run all the way out FM 977. You could do all the stuff on the East side of I-45 in a few hours.
Then you can head East out towards Livingston. FM 350 up to Moscow is fun. FM 942 between FM 350 and FM 1745 is great. FM 1745 may not show on the maps but it runs over to Chester on US 287 and then to Colmesneil on US 69. In Colmesneil there is a good place to eat called Texas Star Cafe. From Colmesneil, either direction on FM 256 to Us 190 is fun. There is little if any traffic on these roads.
If you get South of US 190, there are some fun roads but they tend to have a lot of traffic on them on the weekends. Roads of interest are FM 1276, 943, 2798, and 223 out of Shepard. If you go farther North up around Hemphill and San Augustine, there are some great roads! But that is an all day affair.
Let's see... There is also the area Just West of Lake Lvingston. Roads of note there are FM's 946, 945, 224, 2693 and 1725, also Hwy 150 and 156. You could easily hit most of those in a few hours. FM 946 has been recently blacktopped and is really sweet. You may get some traffic on these roads but not so bad you can't easily pass it.
That ought to keep you busy for a while!
Adios,