I was looking for ideas for random encounters for a party travelling with a caravan. I found several free online. During my search I also found a series (four or five volumes) of published supplements each containing roughly five detailed encounters tailored toward travel. As luck would have it I've run out of ideas for travel encounters, but my party is still travelling so now I want to find these supplements.
Here are some details that I remember from the Amazon description and reviews. There was one encounter where players were lured off the path by pixies and forced to join an enchanted dance. In another the travelers encounter a circus or carnival in which the attending guests kept disappearing.
I can't remember if these were for d20, Pathfinder or D&D, but I believe they were available as both print and ebooks.