That is where I will put my next one(if I do it myself). It puts a little strain on the plug, but it is high enough to sit on top of whatever you have in the bed. I did it where I did because it had the greatest distance between inner and outer walls and I was using the Bargman 90* molded plug.
2012 Sandpiper 365SAQ weighing @ 15k, Onan, 2nd air, slide toppers, TST
2013 F350 6.7L Lariat 4x4 CC DRW,Viair 1007, Ride-Rites, Edge CTS, B&W
2001 Chevy 3500CC DRW 4x4, 8.1L, 4.10 gears w/ Detroit TrueTrac
2001 Ford Excursion Limited 4x4 7.3L,V/B Spring Mod, ProComps, Hellwig Swaybar, & other 'Necessities'