The Vantus Mine Key, tr_m1_ito_fw_keyvantus01, which is given to you at the beginning of the quest "Miner Problems", is supposed to open the locked door to Vantus Mine: Packing Room, but it also opens the locked upstairs door in Firewatch, Vantus Manor, allowing you to access the bedroom and steal everything inside.
Whilst doing "Jobs at the Docks" I entered Ramaran Manor (while visiting Bodrum for an unrelated quest) and I received the journal entry for being caught trespassing for the later quest, breaking progression and failing the future quest before I could start it.
Looting the Ring of Respite will update the Journal with the Ring's respective Imperial Cult quest, even if you have not already started the quest and are not a part of the IC.
Nalen Ammadhubi inhabits one of the towers of Windbreaker Keep. The items and containers in the cell are arranged in a way that implies they are his and that is where he lives, but the ownership flags are not set to reflect this.
