I have been unable to find a ‘free’ way to get access to Mahogany Hall and to Wilmots end.
I know there are ways to ‘buy’ entrance but I assume like with the Palace, the Labyrinth, the Forgotten Quarter and the University, there are free ways to get access once you have completed some task / some card.
Is that not the case for those two? My skills are high enough (shadowy 91 core -114 with items /// Watchful 103 - 134 with items).
Note that the card offers another opportunity to grind Connections to the Great Gate!
If you wish to increase it and don’t have any business try to delay unlocking Wilmot’s End. Doing so locks you from the card.
I was unlucky to rush and open the route and realized only afterwards that I made a small mistake! But this is from my collectionist/hoarder perspective! :)