Battery shut-off switch on Elkmont

We use our trailer on average once every three weeks to a month. We have found that this is sometimes enough to kill the battery between uses, depending on circumstances. The trailer is kept in a storage lot, so there is no access to 120V to keep the battery charged.

Our previous trailer had the battery on the tongue in a marine-battery-style plastic two-piece case. Rather than having to disconnect the battery manually each time, I installed a battery switch like this: http://www.harborfreight.com/battery...tch-92688.html integrated into the case cover, which made disconnecting and reconnecting the battery a breeze.

I want to do the same thing with the Elkmont, but the battery is located underneath the couch, in the middle of the trailer. The plastic case has a vent pipe (I'm assuming to vent hydrogen or other gases out of the trailer in the evnt of a battery malfunction).

Has anyone modified their Elkmont to add an easily-accessible battery switch? I'm getting a bit tired of tearing the couch cushions off every time I shut down or go to use the trailer...