Walking viewpoints

[TrashcanPatrol]

I've been looking at this for a bit now, and I saw a demo/something where the viewpoint was inside of a mini cooper. The user would press Up and Down to move forward and backward, and with the mouse they could look around. However, the left and right were bound to the body of the car.
I tinkered with the script a bit and removed the viewpoint from the car, but the farthest I could get to freeing the left and right views was to make the viewpoint rotate left and right when pressed. It doesn't let you move forward/backward AND rotate right/left, though.
I guess my questions are...
-How do I get it so that I can move the viewpoint forward without the mouse, and look around while moving but be unbound to the body?
-Is there any way to walk forward/backwards and strafe left/right with the keyboard, and look around with the mouse (without having to click, and without being bound to the body)?

Apologies for my lack of knowledge, I'm a bit new to this >_<