Which Way?

This is difficult to prep for. There are very different encounters to develop depending on how the party decides to move ahead in their quest. I think that means we're going to be doing some roundy-roundy here, in order to cover all bases. There need to be four points covered, the conditions and elements of the journey by land and sea, and a sample encounter of each.
I'm starting with the lake. The barge makes a weekly trip from Chance to Aronsburg and back. The lake is about 20 miles from town to town, and the barge takes two full days to make the crossing each way, with a day layover for loading and unloading. The barge stays in Aronsburg an extra day on Sundays, leaving for Chance every Monday morning. Due to the shallow depths in many places, the barge is poled much of the way by a crew of six who work in two person shifts. The barge stops about half way across the lake. The towns shored up a sandbar near the middle of the lake that can be used as an anchor point and fortification against attack. Generally, the crew remain on the barge, but the fortification is there if needed. This part of the journey is the most dangerous. The threat of attack in the night by lizard folk from the marsh is almost guaranteed.
It has almost become ritual, with the barge anchoring, watch being set, an attack made from some direction, and the monsters repelled. The lizard folk seem to be interested in grabbing food and small trinkets, so the boatmen often leave a crate or two of food and odds and ends near the edge for easy picking. The fights are almost choreographed to allow them to take the food and go.
Now and again, there is more to the fights. On this occasion, the lizard folk have gotten to the island first, and set an ambush for the barge when it arrives. There are many lizard folk surrounding the area, waiting for a sign to attack.