As @yahwho mentioned, your worlds are stored in the "Worlds" folder in your game directory (when using the Steam version, you can also get to the game menu by rightclicking on RW in Steam -> Properties -> Local files -> Browse local files)
Other player data, for example Blueprints, are also stored in the game directory (blueprints can be found in the "Blueprints" folder).
The game config (containing graphics settings, key bindings) is stored in a file called "config.properties" in your game dir
Thanks I took the worlds folder and created a .rar file of it for backup along with the configs. Made a folder called Backup in the Main Directory and also sent a copy over to a CD-ROM as a just in case. Thanks again guys, now if I could just find my old blueprints that are buried somewhere in these forums I could also begin my Subscriber Specials again. By the way wanted to ask if flowing water is in the works and how that impact world saves if rivers, creeks, misc rocks and boulders were added? I'm looking into JSON files to add stones, pebbles, boulders and possibly new plant types for wet zones; such as anywhere it rains with the exception of deserts and other dry arid zones. Opis Model Creator works beautiful with creating new types of blocks, and decoratives to the game.