Hi, Jake. To drain the hot water tank, you remove the white nylon drain plug and the water will just run out. Mine uses a 7/8" socket, or you might get it out using a 7/8" wrench. I've used both. Once the tank has drained, reinsert the drain plug to keep spiders out of the tank.
I've found the 7/8" socket works best using a 6" extension because the drain plug sits behind some other components and is a tiny bit difficult to get to.
To raise the low corner, you need to shorten the lifting cable for that corner. If it's 1/8" low, that's all it will need to be shortened. The adjusting bolts are probably in front of your wheel(s) on the street side. Trace the cables underneath the trailer to see which bolt you need to move out. It is held in place by an adjusting nut and a lock nut.
- Jack