I am pretty sleepy so I will keep this short and post screenshots in the morning. Or in the later morning :-) Today I spent about two hours exploring the dungeons Wrong and Destard. Wrong was strange--there is a electrical field blocking a door in the northeast corner of the first level, but I never did find a swich that would turn it off. Wrong was also strange because its bottom level is just a big, pointless and empty room. It was clearly intended to have once been a jail, with lots of rooms including some with the ever popular murderous children in them. I found the map piece in a hidden chamber behind a hydra. I forgot the story of the guy who lost it, but it seems odd that the dude managed to escape and survive since there was no easy way to get away.
After this I was briefly confused because I had only six pieces of the map, and I thought I should have seven. This was incorrect! After searching uselessly for awhile in places I had been, I spent more than three seconds thinking and realized I already had it. The next task was to hit Trinsic and speak to the cook, who again sent me to Destard. My Destard strategy was to explore in solo mode while invisible, then make a dash for the ladders. This worked well until the third level, which led down to a fourth level full of dragons and which was simply gigantic in size. Huge open caves are a much bigger pain to map than smaller caves, so I didn't even bother once I found the room with the eggs. Surviving this was tough. My strategy was pretty violent: I killed all my party members, save myself and Dupre, put on some rings, and hit the treasure trove. Then I went back to the corpses and cast help. Had I been more keen on reasonableness I might have simply killed them with lava or turned invisible while fighting a dragon.
The cook gave me directions to the final few map pieces--a dude on Dagger Island and a dude somewhere in the woods near Empath Abbey. I remember Crazy Dagger Isle Hermit guy, but I don't remember the Empath Abbey person. Humorously, a small amount of brainpower pretty much gives away where the treasure is at this point, and I remember finding it with ease the first time I played simply by following a partial map. However, it will be amusing to find the last few pieces this time I think. From here I think the game proceeds rapidly to its conclusion--a lot of talking, but not so much mapping huge dungeons.
To answer some questions--yes, after this comes Savage Empire and Martian Dreams, then Underworld. I will try to follow release dates in a rough manner, though I don't know the precise dates for the Runes of Virtue games with respect to the other games--ROV 1 follows Ultima VII by a few months, but both Ultima VIII and ROV 2 were released in March of 1994, and I'm not sure who was first. I have played Savage Empire, but gave up towards the end, while I came extremely close to finishing Martian Dreams, but a bug forced me to quit. Both games seem vastly more difficult than Ultima VI.