The Island is a live action one-shot adventure for Call of Cthulhu available from DriveThruRPG. It looks like fun--there are lots of different characters for players to choose from and one in particular is desperate, broke, duplicitous, and otherwise a total hoot to play. The characters seem well enough connected to each other to keep anyone from feeling left out, and every one has a 'Who and what you know' on the sheet itself. If I had to quibble with this portion of the game it would be that some of them are gender-specific when they don't have to be. 8 men, 2 women, and 2 that could go either way--I've seen worse ratios. Still, I'd make as many roles gender neutral as possible i.e. all of them, except for necessarily-heterosexual couples. The head of a smuggling ring a woman? Why not? It's a stretch to have a woman head of a bank in '47, but for a game it's not out of line--you could fall back on the ' heiress' trope for that.
The characters are the most important part and the author has that nailed. The story's vital too and I felt he short-shifted there. The story has a beginning and one ending but no guidelines for what to do in between. If the plot stalls, the GM is on his own. There's much plot inside the character descriptions, but I feel the GM needs a backstage version of all this. A chart or at least a detailed global plot to make the big picture clearer.
Generally speaking though "The Island" covers the points I consider necessary for a good LARP. Its focus is on story between characters, and it includes props to keep the game physical.
It has interconnectedness. Each character should be connected to at least two other characters. Looks good on that point.
Redundancy. Any plot point or object should be in at least two different sets of hands, in case one of them is clueless or paranoid and won't play it. Clem's letters and Straker's cross could get lost, and while neither is vital to the arc it would be sad to lose either.
Not on a rail. Allow for any ending the players can think of. Try to anticipate alternate endings and note them in the Ending the Adventure section. Even Cthulhu players like to change up the endings once in awhile.
Bottle your players. An island is an excellent device for keeping them together--as long as the storm destroyed all boats. A little contrived, but it works.