Help deciding whether to sign FT offer

Hi everyone,

Recently just got an offer for FT IB in a low tier city that pays surprisingly very well. Offer letter didn't have a deadline, however it did say I would need to start working within a couple of weeks. Doing this would require getting a new apartment, car, and moving everything in. However, I have been interviewing with a BB for S&T in NYC. Emailed and told the guy during the interview that I have a pending offer, however he told me they are still interviewing and there is no set timeline. 

What should I do in this situation? Should I ask for an extension, due to the fact I have deal with the logistics of moving to this new city and hope I finish the interview process by then? Should I sign the contract and renege? Although, these bankers have been nothing but kind to me throughout the process. Appreciate anyone's help or advice. Thanks in advance!