Colliding an object

I'm taking my first steps through Unity, as a follow up to this question:

I now realized that I don't know how to make a collider actually collide. Now I have a GameObject I move around instead of the camera, and the camera is a child to that object. It has a box collider, and there're four other box colliders around the level so it will collide against them.. and it's not working, of course, because I was changing the position variable by hand. What do I do so this collides? use a rigidBody and apply forces to it? is there a way to put a maxVelocity on it? I can't see one, besides a rigidbody seems sort of overkill for what I'm trying to do. Otherwise I guess I just put mass 1, and export drag and force, but I'd much rather work with a maxSpeed, because drag will also affect the acceleration rate

Mark the colliders as triggers. Attach a script to the box that moves it back into the visible area when a trigger event occurs and the other object is one of the invisible walls.