B+ motorhomes

Just got back from a quick weekend trip to Steamboat Springs. The Trail-Lite ran great and I got near 13 mpg. I'm still scratching my head as to where to mount a 1750 watt inverter close to the batteries and in a dry cozy place. I've been thinking if creating my own "storage bin" by mounting some sort of Rubbermaid bin on the under carriage near the batteries. A bit worried about ventilation/ water entry issues though. I guess I could drill through the floor and mount somewhere inside coach, but haven't worked out any good locations for that yet. I use the space under the couch for storing memory foam topper and bedding. Batteries are located under this area in just an open tray on under carriage. I've spent a bit of time crawling around under the rig, but still can't come to a decision. Oh well, they say pre-installation takes ten times as long as actually doing it.