Yay for it being on GOG! It was in Alpha for so long, that I figured it would never see the light of day. So I just bought the alpha on Steam and played it (like millions of others). I'm glad that money helps the devs finish their product. It was really good last I played it (just as it was hitting beta). But I quit playing it, waiting for the full release.
It's a definite GOG buy at some point for me, too. I make sure if it's a game I want to play in 10 years, that it's on my GOG account. And Kerbal is one of those games that I'll be playing when I'm 70 -- unless they make it better later with a Kerbal 2. :)
I haven't gone looking for mods. Are there any mods that turn it into the real solar system and use real astronauts? It'd be neat as an added science lesson for my kids as we blast off to places.
Lastly, I have to tell the story of me going to the Mun. Early last summer, I tried going to the Mun 50 times. I didn't know about the quick-save or quick-load feature (F5 and F9), so my missions were always rogue-like get-her-done style of missions. And I just could not get to the Mun and back. I had a lander stuck on the Mun with an astronaut and a bunch of debris from bad landings. I was about to give up. Then I went on vacation.
On my way back, we stopped in Hunstville, AL where they do space camp. They had schematics of the Saturn V rocket (and an actual Saturn V stretching up into the sky). And I noticed some design decisions that NASA had done to Saturn V that made much better sense than my own designs.
So I redesigned my rocket, much close to the Saturn V rocket. I also changed my lander a bit to mimic the real lander. (I wont say exactly what I did b/c figuring those things out are all part of the fun!)
Using those design modifications, I got to the Mun, visited the other moon (I forget its name now) and got back to Kerbal with fuel to spare. It was pretty awesome. Go NASA!
Oh -- one my story. I can't remember exactly where in the whole scheme of things it happened, but once I ran out of fuel just outside of Kerbal's atmosphere. So I got my kerbal out of the spaceship and literally pushed the rocket into a different orbit, touching the atmosphere, and setting it up for a successful descent. That was a very long, hard mission. It involved a lot of pushing.
Have fun with the game, everyone!