I have a shop cell set up identically to the Riverwood Trader, yet my merchant won't stop yelling at me for trespassing.

How do I make it so that the player is allowed to be in there during store hours? I copied the cell info, lists, and proprietor's packages exactly from Lucan and the Riverwood Trader, yet it isn't working as expected. I have several other stores that I had marked as public until now, so I assume they will no longer work properly either.

Any ideas what I could be missing here?

Don't you have to put a schedule on the building? So the doors will lock and unlock. Perhaps the Bark trigger is tied to that schedule.

I don't see a building schedule anywhere, and the doors do unlock properly. That's controlled by the store owners 'sell' package, which is marked to unlock doors when it starts and he is selling. Then the doors lock when he/she sleeps.

The doors are unlocking properly it seems, but he refuses to accept that I'm allowed within sight in his shop...

The CK Wiki says all the doors have to unlock, is there one, maybe upstairs that has not unlocked?

Is your Owner NPC stated on the Lock List for the Interior?

Finally, do all characters have this issue, or just the one?

The Riverwood trader has a faction associated to the vendor called 'ServicesRiverwoodRiverwoodTrader'. In the vendor tab there is a start and end time, which also matches Lucan Valerius' sell package. Could it be that you need this type of additional faction?