I will be running this as a demo tomorrow and having read through it I can tell you couldn't realistically play this for a 4 - 6 player group in anything less than about 8 - 10 hours - a two or three average gaming sessions for me. I have a three hours slot tomorrow morning.
So, any thoughts from people on cutting the mission down to something more manageable?
My current plan would be to forget Part 1 altogether and dropping the first part of Part 2 as well, starting with a preamble explaining the mission so far and launching directly into saving the survivors of the crashed Valkyrie. That means we have a tactical combat, followed by a breather as the team re-equip, then the battle on to the River, over the Bridge and the final conflict before the end.
Yes, typing it out like this I can see it seems short, but it still represents at least three pitched battles and a bit of role playing. More than enough for a 3 hour session.