Giving out XP now:
Please update your character sheets, and if your character receives an XP bonus for Wisdom, please also add that.
With Borimer flying, you push off in the boats per Kahan's suggestion (with Fingas taking Borimer's place):
Front Middle Last
Leo, Tahldar, Fingas
Kahan, Geebo, Shae
Flying: Borimer
The river is flowing at a rate of about 3-5 mph, depending on location (about 5-8 feet per second). This is fast, but not too fast that you can't briefly talk and adjust.
The first thing you notice as you go downstream is that the paddles help steer and push, but given that lava is much denser than water, it takes more strength.
The lava river width is generally 40-50 feet. I assume you go single file instead of side by side generally.
There are many little stone "islands" in the center of the lava (marked 24C). For each one passed, the following will occur:
Front of boat: Roll DEX to steer to avoid collision.
Back of boat: Roll STR to row away from island.
Roll is at -1/2 (rounded down) for every mph the river flows.
If either miss the roll, then every person in boat makes save vs. petrification. Failed save means I will roll on a secret chart for results, which could be from no effect to falling out of raft (ouch!).
You can alter these dangers as desired by trying other things too (spells or whatever).
You notice that the lava river seems to have many curves to the right. You pass the first curve.
You are now approaching the first island to evade.
You also see ahead that the current separates into two passages, one on the north and one on the south. The narrow tunnels are only slightly wider than a single raft (about 5 feet), will not allow oars to be used in the lava, and each raft will need to pick a tunnel (top or bottom).