You can walk up the hill and visit the house any time you want. The guard doesn't even care any more. The house is in fairly bad shape. There was talk a couple of years ago about turning it into a museum, but the idea was nixed.
As you arrive at San Cristobal on the carretera, take the exit that goes AWAY from San Cristobal. Then ask directions. While there, I recommend you also visit the Cuevas Pomier. Take your own flashlights, as the wires for the lights in the caves was stolen.