Compared to some water treks, the Comal jaunt is Lilliputian. The shortest navigable river in Texas, the watery playground draws friends and families galore. Hop in—and go. It’s that easy. Two to three hours later, you’ll come across an exit spot, and if you started early enough, you can repeat the fun. A tributary of the Guadalupe River, the Comal feels like a lazy river, as it transports you at almost slow motion speed.