Rodents, Disposing of poisons
A mouse once chewed through the 110 wiring on our Airstream during the winter. When we hooked it up in the spring to prepare for a trip, the wiring caught fire. (Family bonding through TT use, I gotta million stories!) Whatever method you choose to prevent or dipsose of them, rodents are best prevented from keeping house in your TT. The only method I've found that works well is trying to seal them out. They will chew through many materials, of course, but I have found that they don't like to chew metal strips. At home I use steel wool and caulk around pipes to keep them out.
Someone asked about disposing of antifreeze, etc. A general rule of thumb is that if it is toxic it doesn't belong in the sewer. Most sewers empty directly into streams and rivers. Those that don't must be treated before reaching streams and sewers. That stuff is hard to get out of the water! Best to dispose of it through your local hazardous waste disposal program (call the county).