Rain does not ruin this region. Trying to force a river day through bad conditions does.
Use the culture collection as a real itinerary.
Spend the morning with New Braunfels history, take a long lunch, explore Gruene under cover and save music for evening. If storms have changed water conditions, do not assume tomorrow’s plan is unchanged.
Sources & further reading
Tony’s Guide separates documented history from interpretation. If you spot an error or know of a primary source we should examine, send a correction.