Using plywood (known as "dance floor") is industry standard, probably more common than track for interior dolly shots because of the enhanced flexibility. Top grade sheets of 4x8 are used, and they are covered in a staggered fashion with 4x8 sheets of thin plastic (I've seen various materials used) that are then taped at the seams to make a smooth, even surface.

I don't think I've yet seen a crane ride on curved track; the arc of the arm generally provides enough flexibility to get the lens where it is needed while riding straight track. Also, while skatewheels are common for dollies, the crane/track combos I've seen use hard wheels on the track because of the weight issues mentioned here. The length of the arm tends to dilute the high-frequency vibrations that can be produced by the hard wheels.