How can a 3D-autopilot be implemented in a space opera game?
I didn't go too in-depth with your solution, but if your aim is to simplify it to the point where it's an analytic solution, then you can just use a Hohmann interplanetary transfer orbit, right? Is this not similar to what you did? This paper explains it better than I ever could: http://ocw.mit.edu/c...07F09_Lec17.pdf
And yeah, like alvaro is implying, and as I'm sure you already know, it's a bit more complicated if you want to take a whole lot of bodies into consideration. It's no longer just "a couple of two-body problems stitched together". At best, it would likely mean having to correct your course due to the many minor perturbations that you undergo as you travel from one planet to the other. At worst, it would mean having to postpone launch or taking a highly inoptimal course to ensure that your ship won't run smack dab into some other planet halfway through the journey. Have fun with that. If you succeed, you should probably be working at NASA. ;)