Door Simulation

You can pull off the door movement fairly easily using a basic motion study. You'll want to create hinges for the door and use appropriate assembly mates to allow the door to swing open, then click the Motion Study tab at the very bottom of the solidworks window. From here, you can set up time-based keyframes for the closed door and then the open door a few seconds later. Solidworks fills in the animation in-between.

The walk-through may unfortunately be more difficult because of the way the camera behaves. While Solidworks Motion allows you to set keyframes for camera angle and zoom, as far as I know you can't actually position the camera in front of other objects. You'll always see the outside of the structure unless you go through the trouble of setting keyframes to hide walls and objects that you want to appear 'behind' the camera. With a lot of time and effort, you may be able to make it convincing, though.

The door is easy.  Just add a hinge with the appropriate mates.  The only issue for what you want to do is to keep the door from rotating 360 degrees.

The walk through can be accomplished by saving your file as VRML file.  Then you have use a VRML viewer for the walk through  You can get a lot of information on VRML at http://vrmlworks.crispen.org/.  You need to choose your camera path carefully because you can walk through your walls, or doors for that matter.