The simplest way is to splice into the positive and negative wires going to your 12 volt accessory port, using an inline fuse of say 5 amps. That circuit is live in Accessory and Run modes.
As far as switch location, you need to get creative, a protected waterproof one next to that round outlet will work, but it is fairly vulnerable to damage.
I 3D printed a switch mount to go up high in the upper left corner of my GFC Topper. I have yet to install it, that is going to be in the next few days , I hope.
IMO the stock lights are pretty useless. I built harnesses and bought lights for the bed from Kingpin Lighting. Really high quality but not inexpensive. About $65 per each 12” light. (Of course they upgraded right after I bought them to have both white and red light to protect your night vision) I put in 5, one on the underside of my hard folding top and one vertically in each rear corner. I put one on each side under the rail about 1/2 way in the box.
since I have an XLT so I don’t have any puddle lights. I decided to add some plugs into my wire loom so that could add lights midship. I bought 4 from Lux Lighting that are about 3 inches long and have really strong magnets. Also high quality and about $18 each. I ran the power wire up to the battery and installed a wireless switch I got from Amazon. I have 3 switches, 2 are programable. They can be set to on/off or on / off up to 5 minutes. I keep one in the little cubby next to the steering wheel, one on my keychain and one in the bed under the cover by the PowerPoints.