An asphalt grinder makes quick work of the old driveway, truning blacktop into a gravel mix that will serve as a bed for the new, reconfigured drive. Inside, Mark Schaub shows Steve the new sealed gas fireplace in the guest bedroom; a last-minute discovery of a Massachusetts-only code prevented the use of the open unit we had hope to use. Nonetheless, the new solution is a handsome unit, remote-controlled, with a period English tile surround and hearth and with a mantle made from pieces of the old master bathroom fireplace, which was taken out. Landscape architect David Hawk walks Steve along the rapidly developing new driveway, which gives an entirely different arrival experience than the old 16-foot-wide straight approach it replaces. Richard Trethewey shows off a new energy-recovery ventilator that not only changes the house's air (essential, given how highly insulated we've made it) but harvests heat and moisture from the exiting stale air in the winter, adding both to the incoming