I don't see it being a problem, I live south of you in Cape Coral and have had chipboard cabinets in my garage for over 16 years. No problems with sag or anything. As long as you don't let rain hit it or spray it down with water you should be fine. Just seal the wood with a few coats of polyurethane or paint and you should be good. As for the electronics I would keep the pc mounted in a regular pc case.