I'm a bit behind the curve, but in a prior version I was going to see if I could mod in a module that (for significant weight penalty) when activated would accept
simple orientation instructions to pass to the controls so that you could make the long but low burns that I always favoured (but need regular attention to adjust the aim for, as you go round the orbit, rather than either tumbling randomly or always pointing in the same direction w.r.t. stellar references, and as such could point the wrong direction half the time). I was also considering even longer duration/lower impulse thrust via ion-drive addition[1]. With that
always directed in the direction of the orbit (or perpendicular to it, or some other marked angle) I was hoping to emulate the SMART mission, somewhat, with a long-duration low-fuel transit.
It would not be a full-on auto-pilot, of course. Although I'd also wondered about a
crewless module that you
only pre-program, and can't control much at all once launched[2]. Perhaps coupled with a sighting-module (again not cheap, weight-wise) to allow something like "aim 15 degrees ahead of moon position" for some or all of the time it is activated.
Anyway:
a) It's probably already been done by other modders (and there's a large amount of
this thread that I've still to read through, where such might be mentioned), who have more time on their hands,
b) I note that Ion drive and better plane-defined auto-orientation (if I understand it correctly, what I was looking to emulate) are now in the game. (Or about to be in, anyway, at least to facilitate in-orbit dockings).
As such, I may well be satisfied. Or at least differently-frustrated!
(Strange how I want to implement mods myself (and know myself to be capable of it, I just need the free time), when I'm actually quite averse to using
other people's mods to 'adulterate' the purity of the original game release. It's a strange ethic.
)
[1] For which I was going to need to have added something like a specialist tank of accelerant fuel (xenon?), plus my own version of (heavy) nuclear power generation unit or (atmospherically vulnerable) solar panels. Again, I see that at least some of this is part of the newer release, if not in the current one that I've not fully acquainted myself with yet!
[2] I sort of assume, in my own particular version of Kerbal reality, that Jeb/whoever is the pilot, as your proxy, rather than being directed by CapCom that just happens to have three Kerbonauts strapped into it the can because the planet apparently lacks dogs and monkeys...