Lyle, if I was ordering, and had the option, I'd get the 50 amp.
I do have a Dometic 15,000 AC, that cools really well!
I just have 30 amp service, but I've never had a problem tripping a breaker. I have heard that some of the newer 15K ACs, use less power than some of the older 13,500.
I run my WH on electric, plus the fridge, and have never been careful, using the microwave, AC, coffee pot, etc. I have a volt meter plugged in, but never have seen it in the danger zone.
I'm anxious to hear more about your new FW. It is always exciting, even when it is someone else getting a new trailer.
Jerry