I intend to use the frame of LoF to build my next campaign, but I'm not a fan of the very start of it.
Starting In Media Res can be a good thing - especially if you have a large table of players. Get the people at the table and get the dice rolling as fast as possible, let the character development happen later. When you have a smaller (4 or less players) table, I really prefer to have the players less focused on rolling dice/crunching numbers and instead thinking about who their character is and finding its voice.
Has anyone built the beginning of the campaign out to include more than "...you wake up in a bed..."
"You've been hired to guard a caravan, after spending a week to get there (feel free to describe yourselves) you're finally almost there - OH LOOK A FIRE!"
I like Barator's idea that builds a story of the PC's being fill-ins to replace some bad hires, but that's more off screen interactions. I'd like some ideas about how they get chosen or hired. and what happens BEFORE "...OH LOOK A FIRE!"