Look under the bed. Might find some 12V wires there. Snake from celing fixture over is what I would try, not knowing more about your rig. Running snake wire front to back is more likely to encounter a roof support. Depending on your location, there is IKEA south of Chicago. The lights also come with color changing, but DW said NO! No need to use the power supply that comes with lights, just wire direct. Also, Lowes and HD have some, not as good for the job, and cost a lot more. Here is a link, and you can order online via mail.
vendor for lights