I gotta say: Prepare yourself for frustration. In my opinion, the KSP modding scene has really taken a dive. Many mods have changed hands over and over again as their original authors, and later generous volunteer maintainers, have stopped playing the game. There's no consistent UI for mods — put MechJeb and Kerbal Engineer side by side on the screen and it's like they're from totally different games — and keeping mods compatible with the various dot releases must be a real pain. Even with CKAN, which is as good as it gets for players, getting seriously into modding means wading through a sea of unbalanced parts and weird, hard-to-use UIs.

I'm not saying don't do it. I'm just saying be careful not to end up spending more time getting all your mods to work together than actually playing the game.