C (my spouse's current place of employment, which also offered me a t -t job) has been somewhat vague on what the position they've extended me will entail (though that's getting better). Also, no written offer or contract will appear until I've jumped through all the hoops (the job will be advertised, I must apply, there will be an interview, etc.), which is a bit unsettling, though I've been told I WILL be offered the job, and the ad is actually being crafted with me in mind. Finally, I've been made to feel/ have allowed myself to fear inferior for so long within the department where I've currently been adjuncting, that I've been concerned about making the transition onto the tenure track here (though it's a split position between two depts. and my "home" will really be in the other dept.).
How much do you trust them? There are stories of department reneging on such offers which are verbal by definition. (It is probably illegal to guarantee you the position because if they have to do a search, it's a position for which they must do a nation-wide search). Can you get them to do the search ASAP and get you the offer ASAP? You'd hate to hear next year, "well, we meant to open that line but the budget cuts, you know, also the dean retired and the new dean doesn't want to go along with this..."
Not to scare you. Such fixed searches do happen (and do suck for the unsuspecting runner-ups) but I think solving two-body problems are also important...