I got two when I bought my fifth wheel and I wouldn't have it any other way. 2 units will cool down the unit much faster then 1. And you WILL eventually need that second one if you camp in the lower 2/3 of the continental US. I was in Iowa last year a day after Labor Day and it was over 100 degrees.
Don't run the bedroom unit at night - won't need to anyway. Also nice to be able to run only the bedroom unit in the evening while watching TV, etc.
50 amp is no big deal - you can always plug in to a 30 amp unit and run a single AC unit. Only downside is the CGs will charge you more for 50 amp.
Tim