Got one more Q.
The description leaves my unsure: Should I play VL FIRST, and the decisions I make in the DLC will then affect any playthroughs with the REGULAR main campaign, or should I play through the main campaign first, and THEN playing VL will be different, depending on what I do in the main campaign?

So, which way around does this work?

Not before the basic campaign but neither after it.
You should play it during it.
Best story place to visit it is after Season of Bloom questline (you get letter from Varn).
In that place you should leave the main game for a while and start VL instead.
You import your main game save into VL but it is just to use your main character for cut-scenes.

Thanks a lot. So the DLC uses the char from the main storyline.
Sounds like I technically could play Varnhold at any time after I get the letter then, but it would be most consistent story-wise if I hop over right after. :)

Yes, but the cameo by main character is purely cosmetic. It is advisable to finish Varnhold's Lot before The Varnhold Vanishing, as the main campaign will allow you to import Varnhold's Lot save which would affect some quests and allow you to get unique DLC items in your main campaign walkthrough.

You may find additional info in FAQ by Owlcat:
https://www.facebook.com/notes/pathfinder-kingmaker/faq-how-to-import-the-dlc-varnholds-lot-progress-to-the-main-game/1067982820055430/

Uuuh... useful stuff. Thank you.

Me again, so to be a bother.
I played Varnhold (BOY was that Lostlarn Dungeon hard, even carrying 24 Rations to begin with) and finished.
Now, when I started it, I was told to pick a game save from my main game, where I picked the latest save. Since I got frustrated with the DLC at some point, I went back and played a few hours of my main game.

What do I do now? Can I just load my main games latest save (created AFTER starting Varnhold, but BEFORE finishing the DLC) or would that mess things up? I'm also not 100% sure which save I used at the start of Varnhold...

Pickle? Or a non-issue?

Related question: Is there any way in the game to see if my save is "connected" to the Varnhold DLC run or not? Some hint somewhere, some flag showing up, anything?