Ok, I stumbled across "Preferences" right after I posted this and learned the answer to at least two of my questions. You must Pre-Purchase to edit your skin, and it looks like it is done through the site and now any kind of saved file.
Does that mean there is no download when you Pre-Purchase and therefore no way to back-up your map?
I've put well over 30 hours now into my Single Player map with at least another 30+ left before I finish just the stuff I've wanted to do since Day 1. If I Pre-Purchase the game will I get the ability to save the game and map to my computer or is there any other way to back it up? Also, do I have to purchase before I can edit and swap skins? I found the skin helping guide at the top and I assume I can pull up the default skin and modify it then save the newly modified skin in its place, but where do I find this default skin file if Minecraft is brower based? Do I need to Pre-Purchase to have access to this file and folder?
I understand this is meant to be an Alpha and I could live with the loss of my map, but if there was any way at all to back it up I'd love to know how. Thanks.