From experience, if your travels are in the south get the 50 amp and go ahead and get the second AC. Ours came with 50 amp but only one 15k AC. Did not take us long to add the second 13.5k AC. After traveling all day on 95-100 degree days it takes two ACs to cool the trailer down before bedtime. After it cools, then one will keep it cool.
On 30 amp and running a single 15k AC you can still easily trip the park breaker if you operate too much other high current devices such as microwave, water heater, hair dryer, etc. at the same time.
I bought a 25' 30 amp cord with a 50 amp connector on the trailer end that I use when I only need, or only have access to, 30 amp hookups. A standard 50-30 adapter works, but much easier to handle a lighter more flexible 30 amp cable than that 50 amp monster, especially on cold mornings in the mountains.