BumpyRide

Get your apoapsis to where you need it (say, 80km). Then, when you are about 10 seconds away from the apoapsis, turn your engines back on, and circularize your orbit by accelerating your craft to raise your periapsis to the same value as your apoapsis... quite simple, really. Or you can do it in reverse -- if your periapsis is where you need it, and you want to lower your apoapsis, just do a deceleration burn when you are in the vicinity of your periapsis.

Looks good. As far as historical accuracy goes, it's a little off

Got Jeb home from Duna, as well. The hardest part is actually getting from planet to planet. Landing and takeoff are not that bad.