I just wanted to add an additional note here for you, that today I have updated the game to version 1.1. The issues that you reported here with Milton's quest restarting when it shouldn't be, and the subsequent blocked entrance to the mansion should be resolved now in this new version.
You can see the other changes in today's devlog post here if you're curious: https://jayrayhawk.itch.io/dp/devlog/155544/a-new-version-v11-of-death-preposter...
It's a minor update however, and I consider it non-essential for returning players, though would recommend it for folks who haven't downloaded the game yet. So only grab the new version if you feel like it's compelling enough incentive for you.
Thanks again for letting me know about your experience with the game both good and unexpectedly strange! I especially appreciate getting to hear from people who had fun with it.