This point I made got kinda lost in the melee over there, so I'll restate it…
Sean, Dude, one word: paragraphs.
It's an authentic rule of English composition that you start a new paragraph every time a different character starts speaking. That may lead to some short paragraphs, to be sure but is much easier to read than long rambling monstrosities.
(“Who is this guy and why does he think he can give me fan fic advice?”
http://www.ectozone.com/ff.html )
Other constructive criticism:
It's a turn off for many people when they start to read a fan fic and early on you get a scene such as “Ray, Winston, Egon, Venkman, and some new characters you never heard of before get out of the ECTO-1”. Tread carefully with new characters…there's this horrible thing in fan fic circles called “Mary Sue” and a character stuck into a canon group with no explaination is one of the big hallmarks of the phenomenon.
(And if you did explain it, well, I apologize….like I said, I couldn't get far because it was uncomfortable to read)
In your defense, I don't see the idea of the Turtles meeting the Ghostbusters as intrinsically “bad”. They both live in New York, were popular in similar time frames, and even have off-kilter senses of humor. (Heck, you even get four characters and a fight between “They should all wear red masks/tan jump suits” vs. “They should have different colored masks/jump suits” lol)
And yeah, of course Venkman would hit on April O'Niell. You got that part right. Just watch out so Casey Jones doesn't find out and bash Venkman's head in with a golf club :-)