Re: Kat Dennings as Darcy Lewis
FWIW, I don't think Jane's going to go on the tour of the cosmos. (though I could see Jane and Thor having an argument about that).
A while back, someone, maybe on this particular thread, speculated about Darcy and Erik acting as "dispatchers", perhaps on Earth. Actually, I think that's what Jane and Erik will do from Asgard. Darcy would be there too because she's part of the team working on these Einstein-Rosen bridges.