We pretty much do the same as you. Mail the vitamins, but cut the label off the bottle and include it in the package. Declare it as vitamins on the custom forms. We bought the travel space saver bags from walmart. They do the same as the big ziplocks but bigger.
Make sure you have a carry on with a change of clothing for traveling. I have one that fits under the airplane seat in front of me. I carry an MP3 player with nice headphones that cover my ears. They blanket out the noise. They also came with an assortment of adapter plugs for the airlines. When you listen to the movies with good headphones, it makes all the difference in the world how much you enjoy the movie.
Don’t rely on getting batteries down here. Some years they have them and some years they don’t. I mail them. I don’t think I’ve had a problem. I never thought about them being unmailably hazardous. I use the nickle metal hydride batteries a lot. We have a small wall charger and I always keep a good supply. If you are coming for the winter bring a nice pocket flashight. Even better one of those headlights. The LED ones use the least power and are quite bright. Regular batteries seem to do better in the cold, but most of your battery use will be indoors.
If you are a music lover. Bring it down in MP3 format. We use RIO flash players, Lots of people like the hard drive players like IPOD. It’s just too bulky to travel with regular cd’s. I have an external hard drive that has everything on it. It takes up a tenth the space of the old cd books I used to have. The RIO runs off one AAA battery and lasts all day. I just load in the music I want to hear in the morning. Oh yeah I also have a laptop, but the station computers will read my harddrive. They won’t read my RIO without the drivers. We are administrativly locked out from loading any programs on the computers. So I bring down a laptop. I also use it for photos and editing video. If you want more info on that ask in a separate thread.