The idea is as follows:
Day 1: we run
Day 2: capture the castle, put Dessa and Turis in boats!!! (crucial point Leadership+Tactics) {If it' same real (haven't checked), you can build a stable in the starting town, buy Dessa there, get defeated, and then buy her back in the confluence}
Day 3: arrive with Dessa and Turis, put Voy in a boat.
Day 4: Turis takes the Bonfire! This is the hardest part, 6 ravens after all have the first move! When I tried this, I had Grindan, so the ravens cut half my army and made it non-combat capable, but Turis having tactics can protect the snipers, and thanks to leadership can trigger morale for them. BUT! All these thoughts are only for pure SoD... I don't think it will be possible to realize this with the patch :(
Then Voy takes the ravens back, we pass them along the chain and open the gates to the AI (obviously completing the peasant quest in parallel, maybe on day 3 by the way). We enter the AI. In our army we have 79 centaurs, 4 crusaders + something taken from the ravens. In theory, it should be enough for stupid bots. As a result, on day 4 we take both infernos. And Dessa runs to the teleport to learn DD. We visit the blue tent, break out of this confluence, and head towards the blues (maybe put someone in a boat there, killing golems with Wizards and ballista)
Days 5-6: Get DD, and then it's unclear... it seems troops are needed to open the magic forest, vampires and nomads should join us, let's assume we take a dragon, but to manage to take the 2 mines that the nagas guard on day 6, you have to try hard... Plus everything, you need to take the psychs' external dwelling and the second bonfire... In short, I don't know :confused: Maybe Dessa simply won't have enough mp... :(
I didn't check this variant specifically because of the patch (It' same hard to kill ravens, AI, magic dragons)