Ah OK , i thought you play regular AP since this is in AP part of forum, not CW
As for archmages they should be for sure in shop scarlet wind, little island across of castle guarded by relatively weak undead skeletons and archers, i found archmages there every time i played game.
Finding spells is never sure, just hope for luck
And did you check wizard tower on debir ? You get free spell scrolls there in every lvl of tower, but unlike units you can take there for fight scrolls stay in your spellbook after you leave tower and they are free just depend of your spellbook capacity. Try passing at least 1 lvl there to check spells available on 2nd lvl, maybe you get lucky (pass guardian no matter losses just go check spells in shops).
And in almost all my games i found verona map on scarlet wind behind guardian where richard the cruel patrol, so after clearing enemy you can on those islands try kiting only that guardian and again hope for verona map
On side note, try finding somewhere list of usable items in game, expl : amulet of illumination quest items you get in bolo underground, right click it before returning it to the debir temple for 2nd stone. This way you get free 50 leadership.
Antidote potion you find in elon for tortuga tavern quest in rusty anchor, use it and get free 5 mana, etc there are lots of this items in game (at least 20) and nice free rewards from them but i can remember them all
