Payloader looks promising, although there seems to be quite a lot of faffing around involved. I might give it a go if I feel sufficiently frustrated. Baby steps at the moment...
There's a Youtube video where Scott Manley exploits a 0.16 bug that allows you to go anywhere in the Kerbal system using only a small capsule, a fuel tank, and an aerospike engine. I think it basically exploited a truncation error in computing the fuel usage at low thrust or some such. I'm guessing it's been fixed. Some people have way too much time on their hands.
I think you'd need an Orion nuke-powered spaceship to do similar in the real world.