It can be done.
Step 1 - Copy all of the stats for all of the creatures (15). Bump everything to max hit dice. Print all of the stat blocks out on 3' x 5' index cards (6 pt font works well). (Print your PCs on these cards also).
Step 2 - Make a list of all roleplaying NPCs for the crew. Print out a copy of this list to players. Also print out Anhelm's Rage journal.
Step 3 - Copy all of the text descriptions for every event and area description. Paste them into tables, label them, print out one set for every player and cut them out. Place them in the magazine at the appropriate spots. Pass them out to players and read them quickly.
Step 4 - Don't sweat the small stuff. Let Lavinia take care of stocking the ships. Have Amella and Urol worry about the navigation and sailing checks.
Step 5 - Heavy on combat, light on roleplay. Make a mental flowchart for NPC attitudes based on diplomacy checks during Event 1 and Event 2. Rely exclusively on diplomacy rolls with some circumstance bonuses based on player ideas.
Step 6 - Suggest cleric players stock up on wands of create water and/or use their cantrips to do so. Hint that they can skip the restocking of water supplies at the Havekihu River, allowing the group to bypass the Hydra encounter.
Step 7 - Combine Rowyn's climactic showdown with the Brotherhood (Riedran) blockade.
Step 8 - Do not hand out xp. Level characters after the expedition to Tamoachan. Ensure players have their 5th and 6th level characters ready before the game starts.
Step 9 - Ask players to avoid experimentation. What happens when you throw a tree token at a huge creature indoors? What are the rules for sniping? If no one can provide a quick answer and the player can't find it in the rules then ask them to stick with actions they are more familiar with.
Step 10 - Adjudicate combat quickly. Have all of the enemies go on the same initiative order. Prepare each enemies actions for the first few rounds. Make players declare their actions immediately or force them to delay until they are ready to declare. Ensure they resolve their spell effects and damage timely. Most importatnly, pick players who know the game (and the characters they built) extremely well.
We just finished our session a few hours ago and I thought I'd provide these suggestions for anyone considering marathon gaming. Maybe another thing to add is to play other campaigns that are not marathon sessions to allow more roleplaying. For example, I run a homebrew game with a lot of roleplaying on every other Saturday and one of the other players runs a slower session of Shackled City every Wednesday. And remember that fast paced, high action games are great but are not for everyone.