It's a pretty simple rectangular room.
The stage is elevated about two feet off the floor. All the walls and the ceiling are painted black. The stage is rectangular with a door on the back wall on either side. I'd guess it's 8' x 8', but someone here probably knows the exact specs.
The main seating is right in front of the stage about 10 rows of 10 chairs going back. When it gets crowded, people sit on the side of the room (facing perpendicular to the stage) or on the floor in front of the first row.
In terms of seating, I'd recommend the first elevated row. You might have to look closely at the floor, because the rows aren't all elevated evenly like in a stadium (by the time you hit the back of the theater, the seats are about 4 feet up). I'd recommend sitting against the wall, so you can "read" the stage from left to right.
There's ony one aisle. It's on the left if you're standing on stage facing the audience (is that called "stage left"?). Bathrooms are at the end of the aisle. There are two of them. There's only one entrance into the theatre, it takes you into a hallway that goes past the box office, then down a narrow hall and into a small lobby. If you keep going, through the curtains, you'll be in the theater proper.
If you have time, check out the historical exhibit in the lobby. See all your favorite stars back when they were young. Only $.25, and you get free penny candy.