When I started it, I tried to make educated guesses from the clips. Some stuff I got right, others, not so much. The story hinges on the tesseract still being on Earth, so for sure the story must be pre-movie. I also need to remove Thor from the story (sorry, Thor!) I believe I've come up with a suitably technobabble way for Loki to interact with Methos, Clint, etc., and it's no more farfetched than a lot of canon stuff. And lastly, I'm tying the end of the story to the beginning of the movie - actually kind of pleased how that's worked out!
So a little - maybe more - revising, then new stuff. And once I'm done, I'm eager to start the next one!