Well, if asking politely doesn't work, then there's always trying to do it not-so-politely. Granted, given that magic seems to have a major part of Asgard's culture, I wouldn't be surprised if there are magical barriers in addition to physical ones.

[He nods.] Sensible. Starting with your patron and working out may be the best way to go. I suggest Loki being your last resort. He doesn't have the best reputation, and it's possible someone more...trustworthy will offer assistance first. As far as knowledge of the Norse myths, I would be delighted to compile what I know and send it to you.