Caravan encounters

Not sure about anyone else, but I tend to have caravan guarding as one of my go-to campaigns. The PCs act as guards, and get to explore the world a bit. They also have a lot of NPCs around to interact with. It makes running a low level campaign pretty easy. Here's a list of potential encounters for anyone who uses this format:

Caravan Encounters
1.    A stone bridge crosses a river on the trail. Trolls have taken up residence beneath it. It’s possible they can be bargained with for safe passage.
2.    The local barbarian horse tribes are at war. The caravan is approached by a group of them. While parleying, a warband from the other tribe appears on the horizon.
3.    Toll collectors are on the road. They aren’t normally located at this bridge. Are they bandits or have the costs of trade risen without warning?
4.    Ambush! Bandits swarm out of the surrounding forest, intent on plunder.
5.    A tinker’s wagon is set up by the trail. The caravan may stop for repairs and to get news.
6.    Goblin wolf riders begin following the caravan. They are keeping their distance for now. Are there more goblins ahead?
7.    There is a magical drought. The normal watering holes are all dry. Can the mage responsible be bargained with or must he be killed?
8.    Plague town. A major stopping point is suffering from the plague. The caravan must bypass it. Profits and pay will be affected.
9.    Unexpected windfall. The caravan has goods that are desperately needed by a city. They pay very well, and everyone gets a bonus. The local thieves take note.
10.     A wizard joins the caravan as a passenger. Using his magic, the caravan makes much better time than normal.
11.    Some of the caravan guards really don’t like each other. They get into brawls in the evening. People in the caravan are starting to choose sides. One enterprising merchant is taking bets on the fights.
12.    The caravan is passing by an abandoned castle. There are rumors that it contains treasure, now unguarded. The merchants think that it might be worth spending a day investigating.