A couple friends have Craftsman houses (one in Hillcrest, one in Kensington) with historical designations. You can remodel the home, but the facade of the house has to remain the same, and the rest of the remodel has to be in keeping with the original style of the home. Which is kinda of a no-brainer anyway, who the hell is going to do a stucco addition to a Craftsman anyway?
For example, one of the remodels involved extending the upper and lower floors of the home rearward into the back yard, which extended the kitchen and added a new MBR suite. They conformed to the style rules and had no problems.