If you're headed to Austin my recommendation would be Lake Travis or Lake Decker right now. LBJ is my favorite lake in the area, but its been a little more hit or miss lately.
As some have said Travis isn't known for huge fish, however there are some really nice ones in that lake, you just have to weed through them. It's definitely your best bet for numbers right now. A few things I would recommend... days with a warming trend (I.E. when there is a south wind and the weather after a cold front has stabilized and starts to warm up) throwing moving baits. A Storm wiggle wart has been one of the best for me, pay attention to where the wind is blowing and which rock is getting the most direct sunlight. Rock absorbs heat, and even a one degree temp difference will attract fish. Alabama rigs have also been doing really well.
A 1/2 ounce football jig is also a great bait to throw and it has been what I have been getting my bigger bites on. Travis fish love jigs, no secret there.
On colder days when there are blue bird skies the bite can be a little tougher, so this is when I've been switching clients over to a drop shot or a shaky head. Target those 10-25 foot banks and points since those fish will be positioned a little deeper. That football jig is also good but I fish it slower and switch to a chunk trailer.
I haven't been on Decker as much lately since the fishing on Travis has been good, but a chatter bait or a swim jig is a great search bait. If you find an area that you get more than one bite in slow down and throw a senko. I like to go with a very very small pegged tungsten weight and let it fall down in the grass. A fluke is another great bait to fish the same way. Decker has been a pain to launch and load on, but it can be done, just take your time and be careful.
When you get closer to your trip visit my website www.fish512.com
and check out my fishing report section. I live right by Travis and fish it 4-6 days a week, so its the one I report on the most. Shameless plug, but if you opt to bring your own boat for $10 lakeproguides.com has a honey hole report that I write. You get 5 exact pins on a map and accompanying videos explaining how to fish the spots. They update every Thursday and in my opinion is a great resource if you are limited on time and are going to a new lake you're not as familiar with. If you are looking for a guide I would love to take you, all the guides mentioned above are excellent too... take some time to look up reviews and check out everyone's websites and you won't be disappointed!