I have made a traveling merchant. He is riding a horse and has two travel packages that send him from one town to another town. The problem is that he won't sell any stuff, no matter what I do. Things I've done:

1. Made a vendor chest, checked persistent reference. Set the chest as merchant container in the NPC details. Set it as locked/needs key (and tried without any lock). Set the NPC as the owner.

2. Made the merchant and gave him a merchant class. Made sure he has the sell stuff checked in his AI tab (he sells everything but spells). He has 1000 barter gold.

3. Made sure that the travel packages have 'offer services' checked. Apart from that they have 'must reach location' and 'use horse' checked.

But the merchant behaves like a regular NPC. No option to bring up the barter menu. Only thing I can choose is persuasion or cancel. Why? I set up merchants before successfully so it probably has something to do with the travel packages or that he is riding a horse. Any ideas?

EDIT: I should mention that I get the 'invest in shop' topic once my mercantile skill is above the needed value. Of course I also made sure that the merchant container actually has items to sell inside.

Maybe it's because the "must reach location" thing? He won't sell any item before he gets to his target?
Also, did you talk to him when he's at his "service hours"?

Is the merchant using a schedule for his trips, or just patrolling between the two points? There may well be a conflict between the "must reach location" and "offers services" that would be resolved by letting him stop and sell at way-points. But I suspect the whole intent is to have a merchant at a variable point on the road, so maybe we're looking for an alternative to "must reach location".

He has no service hours since he offers services all the time. It seems 'must reach location' is indeed the problem. But without the flag he would constantly switch between the two travel packages when evaluating his packages. He has no schedule, he travels between Anvil and Bruma night and day.

I had a look at Nehrim where they have traveling merchants like the one I want to implement. Pretty clever. They have a script on the merchant that sets a variable OnPackageDone and the packages have a condition to check for the variable. If the player comes closer than 200 units a wander package with no flags is added by addscriptpackage, if the player leaves the package is removed. That way the merchant will travel between the two locations without interruption or AI weirdness but he can still trade with the player. I did it that way in my mod and it works perfectly.

Now I will only need to find the best way to add a guard to the merchant. Tried a follow package, but the guard keeps exactly the distance specified all the time which leads to a stop motion movement because he is faster than the merchant. Accompany didn't work very well either, he doesn't really care much about the merchant with that package (he doesn't even start to run if he's far away, just tries to catch up by walking slowly). If nothing helps I will try to put the guard on a horse with the same speed as well hoping that he won't need to catch up or stop that often.

Maybe slow the horse down to match the guard's walking speed? That would make him more like a lesser companion and less like a guard though