Some embodiments are directed to a tonneau side rail assembly for attachment to a vehicle bed frame that is at least partially covered by a bed frame cover, and that at least partially defines a vehicle exposed area. The tonneau side rail assembly can include a tonneau side rail that is configured to be removably attached to a tonneau assembly. The tonneau side rail can include upper and lower surfaces, an aperture being defined in each of the upper and lower surfaces such that an open space is defined between the apertures. An extender can define longitudinally opposite ends, one of the ends being configured to be rigidly secured to the vehicle bed frame, and the other of the ends being configured to be rigidly secured to the tonneau side rail so as to define a gap between the tonneau side rail and the bed frame cover.