So, it costs $2 to move from Falcon Point to Devil Reef. How does the player get back? Does another investigator have to move to falcon point, pay the $2 and then the player can move back or can the player pay $2 himself and move? What if he doesn't have enough money? I am sorta stuck, two investigators are out there unable to get back.

That's the only guaranteed way back. There are a couple of encounters there that will let you escape, though.

This is one of Innsmouths barbed hooks. You need 2 investigators out there, one to go out to sea, the other to bring them back.

If you are lucky, an encounter gives you a way back alone, and there is also the option of using a gate that has a matching exit somewhere else.

Call Friend, Gate Open at there is another one open some where else, certain Mythos cards can move you, etc

I believe the intention was to introduce some more aspects of teamwork with IH, as can also be seen with Sawbone Alley; I think it is mentioned in a post by Kev Wilson somewhere.