I also work for a small museum. We're in the process of moving to a larger facility, and are doing a lot of exhibit development in conjunction with our architectural firm. It's a major tug of war to NOT become a third party's vision of the typical museum. Small museum's usually have a flavor all their own. They're unique, unlike the bigger institutions which have miles of space, cookie-cutter exhbits, and no docent or educator contact with visitors. Take a look at what works for your place.