I am at on the coast in South Carolina, a combination of the heat and humidity where you are with the addition of salt air thrown in as another element to contend with. I have been reloading in my garage for nearly 10 years, first with five MEC shot shell loaders and since last month, with a Hornady L-n-L AP. My experience has been to keep them well lubricated, clean and (when not in use) covered.
For lubricant I use the Hornady One Shot gun cleaner and lubricant. I actually ordered it by mistake thinking it was their One Shot case lube, best mistake I have made in a very long time, great product. I spray a coating on all exposed metal parts, the dies, shell plate, exterior of the powder measure, etc. I also make sure that I give a shot to all the dies, spare parts, bushings, etc before I store them in plastic containers in the cabinets under my bench. In my case, I store the primers in my safe which has a dehumidifier and my powder is stored in the same cabinet mentioned above. As far as the ram is concerned, I give the zerk fitting a shot of high pressure wheel bearing grease about every 1000 rounds, so far this method has left a very thin coating of grease on the ram.
As far as a cover goes, (don't laugh) I use garbage bags. Cheap, easy to find, one size fits all and easy to replace. I have been covering my MECs with them for years, wrapped around and held in place with a small bungee cord. The MECs still look like new.
Hope this helps.