Trespasser insta-crash

SOLVED !!

I got it people. I made it work !! And... it's so crazy, I kinda make it whithout really believing actually.

See, it bothered me that in my case the game always crash in the beginning of the quest but AFTER the loading screen. So I wondered if there was something bugging in the cutscene with my characters... and I remembered a scene I watched in the DLC trailer where the inquisition leaders came to the palace on mounts.

Then I figure why not ? I reload a save in Skyhold, came to the stable where I had this funny nug-like mount and change it to the standard fereldian horse. To be sure, I also take time to remove my inquisitor armor (but still keeeping it in my inventory). Then I lauch the quest... And it working !!! (and I see my inquisitor on a horse mount decorated, which make me wonder if it was a graphic bug with my horned nug-like mount before, rather than something with the clothes).

Later on, I saw it kinda make sense : other people report crashes after talking to Vivienne in the palace. And in my case, the little companion scene with Vivienne involved the inquisitor and her being undressed (no, not that kind of scene...). So if the bug is with the clothes, it matches.

So, people, if you want to avoid crash bug for now : use the standard mount and keep your regular clothing (yeah, even if they made a wardrobe, you can have fun with it later !). If you still have troubles, you can also run the solutions I remark up there, I doesn't hurt...