a lot depends on what RV you're getting.
5th wheels have much more substantial frames and bumpers, so something like what you're looking at can work.
but on ultra-light trailers, the rear bumper is thin metal, with basic welds and will lose the bikes and rack after a few bumpy trips.
the only thing to do is weld and brace a receiver to the bumper and frame, but this will void the frame's warranty.
you need to tell us what type of RV you're thinking of buying.
and your etrailer link shows all kinds of bike racks with many ways of mounting it.
receiver types, ball mount types, towable types and so on.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC