List of Milestones

Here's how I could see those playing out[1]:

- discovering the way to the basement in Death House (part of intro) - ending Death House (part of intro) - find Tome of Strahd - find Sunsword - find Holy Symbol of Ravenloft - saving the church at Vallaki - defeating the hags at the windmill - lighting the beacon at the silver dragon place - dealing with the Abbot - defeating Baba Lysaga - dealing with Van Richten's tower - teaming up with Ezmerelda - saving the winery - stopping the druids - stopping the werewolves - dealing with the Amber Temple

And those are JUST the ones that make sense according to the book advice! In fact, that's a pretty strict list. Sure you could cross off one or two, but that's still well over level 10 by the time you even get to the castle. This list gets the party to level 17, and that's leaving out a lot of other places that could also easily qualify:

- getting fortunes read by Madame Eva - rescuing Mad Mary's daughter - dealing with Doru - getting Ireena to come with you - getting the "special" NPC foretold by the cards to come with you - saving the girl on the lake - curing the mad wizard - freeing Vallaki from the current burgomaster - also stopping the Watchers - killing the head of the werewolves (could be separate from stopping the werewolves / saving the children) - solving the puzzle of Van Richten / reuniting him with Ezmerelda / helping him with the tiger plot - restoring the winery (as in, return the gems - separate from saving it) - helping the lich in the Amber Temple, or saving the guy from the Amber Temple - raising the boy from Krezk that died - clearing out the monastery (separate from dealing with the Abbot) - defeating the Roc at Tsolenka Pass - defeating the giant goat at Tsolenka Pass - stopping the witches in the castle - finding the Icon of Ravenloft (it's a legendary item, too!) - clearing the crypts in the castle (seriously this is worth something) and/or destroying all of Strahd's vampire spawn - fighting Strahd in the place foretold by the cards

And of course:

- killing Strahd - at that point the game is over but it's still worth a level