Here's a mechanic for determining random encounters.
I've always hated giving the DM sole responsibility for accidentally running into a wandering monster. And when I ran lots of dungeon crawls, I'd always forget to roll. On the other end of the spectrum is one DM I played with who would dramatically roll a d12 for each hour of travel. His encounters were terrible, too. They typically involved an epic battle that completely distracted the party from the main story.
Anyhow, this method puts the chance of encounter in the hands of the PCs. It's a spin off of the 4e Skill Challenge mechanic, and will work well if you want to give your travel a montage feel. For every significant leg of the journey, each player must make a skill check. The DM should determine an appropriate DC/target roll that is consistent for the whole party. The player can choose the skill she wants to employ, as long as she describes how that skill is helping the party along. This is her moment in the montage to detail however she wants. Depending on the size of the group and the pace of the evening, going around the table once or twice should be enough.
Success means the party makes unimpeded progress. Failure means the player gets to play the lead role in a random encounter. Perhaps she is attacked first. Maybe she sets off the trip wire. Maybe she finds the mysterious ring of invisibility.
Alternately, if multiple players fail their checks, the DM could wait until the end of the montage sequence and present an encounter that encompasses the collective failure. That is, Sven's failure means the party will encounter a patrol of goblins, but since Maude also failed, the goblins will have a troll.
|They Have a Cave Troll by Otis Frampton|