So at this point my party is all L6. That's a fair level to start being able, with a little luck and spamming Sleep spells, to take on groups of Castle Guards in Castle Woodhaven. I suppose you could hit Castle Hillstone, but the Triple Crown / Bishop rescue succession starts with the green ticket fights and the green bishop at Woodhaven, so that's where I went.
Two annoyances: First, I discovered/remembered that in certain squares in the castles, you encounter jester NPCs who tell orc jokes. The game demands a disk change, but I don't know how to rig that in DOSbox. I have a sinking suspicion that I actually did this all before and threw in the towel at some point because of the disk-swap problem, and my usually trusty internets search skills are not availing me of a solution.
With teleport orbs and the Jump spell, it's possible to reach the green bishop without triggering the jester and disk-swap stonewall. However, I would swear I accomplished the green Triple Crown (win a green-ticket arena battle in Middlegate, Sandsobar and Atlantium) before I visited the green bishop, but I didn't get the full expected XP reward (3K plus 10K).
Suspecting a missed step, I paid Queen Lamanda a visit. If you stay on the road to the Queen's castle you run into Mandagaul and that encounter would be unbeatable at this level; but with the Mountaineer skill it's not an issue. Again, in Lamanda's castle there are orc-joke-telling jesters that trigger the fatal disk change message. Nothing there gave me a clue as to what I did wrong with the Triple Crown-to-rescue gambit so I tried it over, and hey, that worked. Twice, even, to cheese the party up another level.