I think if you picked your days and stuck next to the banks you would do ok in a 12' jon. I only fish at night on Medina so the boat traffic, wind, and waves are smaller. AJ is right on about Choke, 99 bridge is a good spot for a smaller boat, even up the river will be fine.

Just get some crappie lights and find 20' to 50' of water. They will come to you. Just have to get out there and fish. Get a good graph.