Why not just run an extension cord from the area of the existing inlet to the front..Put the coiled ends in a front/rear compartment,, install an electrical "Hatch" on both ends so when you hook up parked you open the door,(See option) Put the cord into the hatch and on out to the generator or inlet, Close and lock the door..NO need to "Re-wire" at all... and your "Transfer Switch" is automatic
One thing you do NOT want to do is put a 2nd inlet in PARALLEL.. via a transfer switch yes but not in Parallel. The extension cord addresses this safety issue. and whats more... If you ever dump the trailer (Trade in) you can recover the cord for your new ride.