During the first longer than three day outing in our airstream, I came home to find the bathroom floor very wet. I wasn't sure if the hot water heater was leaking or if the toilet was the leaking. I removed the hot water heater and pressure tested the tank. Upon further investigation, I discovered the exact same thing that you had; that being loose bolts on the toilet. The rear bolt was not even hand tight. It appears that in order to tighten the rear bolt, one needs the arm size of a ten year old which is jointed in four places. A rachet end wrench made the job a bit easier.
As far as removing the hot water heater, I was consoled that during reinstallation, I upgraded the gas line, installed a bypass to assist when winterizing, and installed braided flex lines for the hot and cold lines going to and from the tank.
I now check the toilet bolts for tightness when I get the trailer ready in the spring.
86' 31' Sovereign