50 to 30 amp dog bone

If your concern in voltage drop in the campground, switching to the 50 Amp connection will not change anything. Both the 30 and 50 amp connections run off the same service wires. There isn't a set of wires feeding the 30 amp connections and a separate set feeding the 50. What you might gain is a more solid breaker (the 50 isn't flipped off and on as much as the 30) and, as others have said, the fifty plug itself is generally not as worn as the 30. But then again, the 30 amp breakers and 30 amp plugs get changed more frequently during repairs and maintenance exactly for the reason they get more wear and tear, so you might find a 30 in new condition and the corresponding 50 worn.