Apparently you are checking this thread from the road, so I will throw in my two cents.
Of the places that you mentioned on your original list, I have been to
Schoepf's in Belton. I thought it was OK for a place that I was driving through, but I don't know how many miles out of my way I would drive to get there. It is RIGHT off the I-35, though, so if you are passing through and are hungry, it could be worth a stop. The smoked pork chop would be my top recommendation.
It was just a couple of weeks ago that I passed through Tioga and stopped at
Clark's Outpost. I really enjoyed my meal there - combo ribs and brisket, if I remember right, but I'd have to look at my notes to be sure. Don't forget to order a slice of one of their super-tall meringue pies. The chocolate was excellent.
I was told that if I wanted to go to
Van's Pig Stand, I really should go to the one in Shawnee. I did, and I thought it was better than you described. Is it in my Top 5 BBQ joints ever? No, but it is much better than average.
I know it is totally sacrilege to even think this, but my last visit to
Louie Mueller's was not spectacular. I had heard that things have gone slightly downhill since the son took over, but I tried to go in with an open mind. It wasn't bad - and if you've never been - you should go, but at one point, I would have considered LM to be in my Top 5 for BBQ....now, I am not so sure. I don't know that it is so much better than
Southside Market in Elgin or
Smitty's in Lockhart, either.
Of the places you did not mention....
In Dallas (actually Oak Cliff) is an upstart BBQ joint called
Lockhart Barbecue. This is the closest thing you would ever get to central Texas BBQ in Dallas. Both the ribs and the brisket were way above average and the place has a suitable BBQ atmosphere. I think they have only been in business six months or so, but they are making a splash on the Dallas 'que scene.
I don't know if you have plans to make it as far as Houston, but I finally found a BBQ joint that makes me miss the departed
Williams' Smokehouse just a little less. Gatlin's BBQ is on the northwest side of town, and worth a stop for some fine TX brisket. They were out of ribs on the day that I went (admittedly at an off-hour, post-lunch rush), so I hope to make it back to sample.
I don't know if you use Twitter, but an excellent source to follow is @BBQSnob. He also writes a blog for Texas Monthly. I am sure if you are interested, you can find his stuff online. He is great and answers his tweets with excellent recommendations. Hasn't steered me wrong yet.
As it turns out, it looks like I will be in Austin on Tuesday morning, as well, before heading to San Antonio. I may see you over at Franklin's, as it has been on my short list, as well.
Happy travels.