I have the Tekonsha P3. It does everything I want it to and comes with a permanent mount or a clip mount, which allows you to take it out of your truck if desired.
Either P3 or P2 is fine with your trailer. Both are proportional, which is what you want. I don't know what campers world is asking but adventurerv.net is $99 for the P2 and $129 for the P3 with the Chevy wiring harness
I'm not sure there is a "best one" although I have read about more expensive brake controllers that do a little bit more but are many times the cost.
DW, 3 Kids and our Goldens
2012 Shamrock 233S
2008 Toyota Sequoia 5.7L 4WD