Thanks!
The Provinces with crowns are victory point provinces. Each victory point acts like a temple for the purposes of spreading dominion and they are used for determining the winner for a game with a victory condition based on victory points. All special provinces grant victory points but not all victory point provinces are special provinces. Play the adventure map and find out...
Adventure map is the version with all the special provinces. The other one is a no specials version, which does not have any scripted provinces, so Waterdeep, Calimport, Hellgate Keep etc are just normal provinces. The #killfeatures map command annihilates all randomly determined magic sites from the province during game creation so that all scripted sites are guaranteed to appear.
As far as recommended settings go, indie strength is according to taste, but I always play with independents 7. Slows the impossible AI down a bit, but not too much, whereas a lesser indie strength would mean you'd get overrun. Standard gold, standard resources, 150% supplies (which helps AI some with starvation).
Magic sites one or two steps less than default, or default. If you crank it up higher, the gem income is insane. One co-op game against around 20 AI nations with a friend of mine, I had roughly 100 provinces and I did not have any type of gem income less than 20 per turn and some were in the high 30s range without gem generator globals.
On this map I usually use victory by provinces or victory by victory points, with the target VP amount set to between 35 and 50 (out of 100, 50 is maximum you can set).
The number of players that fits on this map is big, so no less than 17 nations, I'd say. But no LA ermor or LA R'lyeh, because the freespawn problem will cause the game to hit the unit limit.
One of the problems is that there are so many start locations that you can end up with somebody having almost a quarter of the map to themselves while seven or eight nations end up starting in a tight cluster, which can lead to some interesting results.