ok let me try to explain how i have it mounted, the grey counter top, in the rear is sitting on the wood frame of the window where the cup holder and ashtray goes it is held down with one screw in each corner. the black leg boards are only mounted to the grey countertop and they just stand and rest on the floor. i did it this way so i can pull the whole counter top thing out only removing 2 screws if i needed to work on wires and stuff. now the wood bottom is a separate piece mounted to the floor using four self tapping screws i then laid out where things would go the battery and fresh water jug are kept from sliding around using .25 cent marking stakes cut to size then screwed to the board then i added the strap on the jug and made a battery hold down out of two large L brackets and an actual battery hold down bolt kit and a piece of 1x4 definitely a lot stronger than the cheap complete hold downs they sell.
ok now on the faucet originally i just had some pvc pipe for a faucet so the switch was necessary to turn the pump on and off. but the the shurflo pump has a pressure cut off so when i changed to the actual faucet i really did not need the switch because when you cut the faucet off the pump shuts off due to the shutoff pressure switch. i left the switch in place and hooked up so one if i want to work on the pump i don't have to unhook the battery and two i did not want an unused hole in the counter top maybe later i can take it out and put a tooth brush holder there or something but for now i will leave it be.