I'd pull the batteries to avoid any leakage, depending on the time frame you do put them away for...I store my batteries in the fridge.
I'd seal off the openings on the engine, as I do live near the ocean and have problems in just a couple of weeks. I was shocked to change a backplate needle valve on an old OS FX 46 and find in just a few months a lot of rust inside, and I was religious about after run oil too.
I just didn't use enough, now I flood the engines with it (Marvel Mystery Oil) as a precaution. Lots of salt air in Florida and this time of year, it rains every single day. Needless to say I dedicated a bedroom with AC to store everything, and leave worthless things in the garage now. http://www.hangtimes.com/id35.html