I don't think I'd have time to play in something this intensive as a main character (it would really depend on which two-week time frame we're talking about), but I'd love to at least play a couple of cameos.
Coming up with an erroneous plot line sounds like loads of fun.
Something like... Frodo and Sam fight their way through 1000's of Orcs to win through to Orodruin where they discover a dragon is guarding the Cracks (love the bit about the dragon, Mnemo).
Or... Shadowfax actually had wings and Gandalf fought the Witchking in the air over the city.
Or a rumor that's a little more canonical (
): each one of the Rohirrim really did bring a hobbit warrior with him on his horse.
I feel like King Elessar would also very likely be blown way out of proportion (I mean, the guy summoned dead people, healed Faramir, Eowyn, and Merry using some plant no one knew had any uses, is way old, and was obviously in close cahoots with the Elves, not to mention Gandalf). Magic powers anyone?