Welcome to the forum. There are a number of threads available on the forum that will give you exactly what you're looking for. You can use the search feature located on every forum page in the top blue bar.
To get you started, here are a couple of links that address your question:
Winterization kit:
http://www.keystonerv.org/forums/sho...ghlight=bypass
The elbow you need is located in post #3
Water Heater Bypass:
http://www.keystonerv.org/forums/sho...ghlight=bypass
The HWH bypass valve is located on the back side of the T valve which is shown in this picture right next to the corrugated black electrical cover.