I quickly ran through the map. The save is quite challenging. I haven't played on the Passage map in a while and forgot how everything is scattered. I laughed a lot when I imagined taking all of this with just one hero.
So, here's how it went. I took the sawmill and mine on the first day. On the second day, I took the Lurelings' dwelling. On the third day, I had 32 Lurelings. If you do all these things with one hero, you'll have to forget about the mine. And there won't be anyone to recruit Lurelings, because I described a small semicircle with a +1 skill point bonus, cleared out the Zombies and Skeletons at the Arena. Next, +1000 experience, mana doubling, cleared out the Dancers on normal difficulty, the Fury support helps clear out the Demons, took the Beasts' dwelling, again Dancers, +1 Knowledge, Demons, took the Defense in the Hut. I took some chests for experience. I bought both starting heroes. I had enough money on the 8th day to buy Fury and Stalker upgrades and build the Town Hall. In a normal game, I would build it in the first week, as well as the Guild, but someone is claiming that the Tavern and Minotaurs are incompatible. So, I built the Minotaurs on the 7th day, even though I didn't really need them...
Hero reached level 9 with a potential mana of 75.
Try playing better without supports.

P.S. Yes, this isn't a tournament, so I didn't try to squeeze out everything possible. Otherwise, I could have used Lucretia to level up someone for general combat... She was just acting as a support, as any other hero could have been in the tavern.