I recently had my best-ever fillup too - 82mpg, and I'm currently about 500 miles into a tank with ~86 reading on the display.
Earlier today I went to get some groceries, and pulled in with this:
What I've found to work is to keep rev's under ~2200 even while accelerating, and to stay in lean burn whenever possible, even if it means bleeding some speed on inclines. I've also experimented with using lean-burn in 4th gear to accelerate (to keep revs up between 1700 and 2000rpm where peak BSFC is), rather than normal burn in 5th, but haven't come to any firm conclusions yet.
Mostly I cruise at ~50mph, with some coasting in neutral and some coasting in gear, depending on what the situation calls for. If the hill is steep enough that I gain speed, I usually coast in gear to keep the battery up, using my regen switch as needed. If the hill is not too steep, and not too long, I keep the engine on and coast which still cuts pumping losses a little (and if you're over ~51mph, it also starts to regen too), and if the incline is long enough I kill the engine. I avoid killing the engine for any but the biggest hills, because lean burn doesn't reengage for maybe 10-15 seconds after restarting the engine.