Three Sisters out by Leakey (RR 335, 336, & 337) is a great ride!!! For sure, every flavor of cop is out (Sheriffs, Constables, DPS, etc) so don't speed much. The corners are sick! Best ride in Texas by far! Here's a link to read about it: http://www.hillcountrycruising.com/the3s.html
stay away from limecreek. they recently started allowing trucks on it and re-paved a portion of it. this had made it quite dangerous. i've been down the road 1000x in cars/bikes and never really had much issues/close calls up until a month ago. I came through one of the 3 hairpins, hit loose asphalt, and low sided immediately. that incident is what led me to become an R6 owner (was an 08 600rr). not saying it will happen to you but a ridiculous amount of people have wrecked on it and quite a few have died. don't drive from to Dallas to Austin just for limecreek. you will be disappointed. take the 3 sisters as suggested and eat lunch at coopers BBQ in llano. i do this atleast once a month with friends and there is no comparison i have found in TX.
It's a fun road for sure. I live literally 10 minutes away from it. But it's not worth a long trip solely to run it.
Recently a lot of houses have been built on it, so lots of driveways and yuppy rich people living out there. The cops and park rangers are HOT on this road now. The residents call the cops when a group of sport bikes are on it (you will want to do laps of the road, especially if you are coming from DFW). Also construction has been heavy out there, so yes there is random gravel out there, and half the road was recently repaved and it still has some loose chip seal in the middle of it. Plenty of grip but if you're in a group rocks will be thrown at ya.
I've also almost gotten taken out by:
-porsches (drivers think the double yellow is a suggestion)
-huge boats on trailers (turns are too tight) There is a put-in for the lake.
And I've almost taken out cyclists riding 3 wide in blind turns up a steep hill going 5mph.
We still run it often but just as one of many roads to enjoy for a north Austin ride, and I don't ride it very fast anymore. Midweek, midday is the best time to be on it.
I agree about the sisters, excellent hill country riding. Just be careful, lots of bikes and bikers claimed. It's worth a day and even an overnight stay. Plus if you're two-up you can drop off your significant other in Fredericksburg for quaint shopping and such.
There are tons of good farm roads all over the place that are great riding, many arguably better than LCR.
Your right about the gravel, we rode it today, gravel is pretty bad in the hair-pins, I came into one today pretty heavy, leaned, and then... Damn gravel put me in the far lane, another buddy went off-road, and another low sided, but he was going about 15mph. Everyone was sliding though the turns. And now after that storm we had last week, but I was some sweet riding still. Get the chance, check out 1174 off of 1431 Canyon Ridge or something like that, pretty sweet road, great up and down hill sweeps and s-turns.