I know this quandary well though I was a post-doc when I took the plunge.

Why does it have to be #1 or the other? Could you see about taking a one-year leave of absence from your tenured position? Seems that if you're successful you'll generate a lot of good publicity for your university. Furthermore, you could try to find a visiting relationship with a university at one of the hubs. For you it would be a good way to meet people and your current university could see you're still serious about the academy even if you only "visit" a minority of your time.