So as a historical linguist by training, of great interest to me is the question of languages: what languages does your team speak, and what periods? Unless it's a much wider range than I realize, I'd like to humbly recommend you take along a polyglot, particularly a dead language polyglot, as an interpreter. J.R.R. Tolkien comes to mind: he's got not only a wide range of languages he's mastered to varying degrees, allowing you to travel throughout much of Europe for the past 2,000 years or more, he can pick up any number of new languages you expose him to! He's also good at reconstruction using the comparative method, so if you end up with a language that's never been attested in writing, he'd be in a position to puzzle some of it out. As a bonus, he likes living in the past more than the present. ;)

I would like to say that he could write up the best account of your travels upon your return, earning you fame and fortune, but more realistically, what would happen would be that after he died, you would find among his papers your experiences incorporated into his unfinished world-building. *g*