Welcome to the forum! I'm very sorry to hear of the loss of your home.
The Retreat you are looking at is about 3' longer than my trailer. It has quite a bit of glass as mine does. You live in Key West. We only use the trailer in the FL panhandle but we stay all over FL and have been to Key West several times.
Obviously, the heat and humidity in the summer is the big concern. I think the area in the panhandle where we stay; surrounded by bays and rivers, is just as humid and hot as Key West....probably more bugs
. We have one 15k AC and one 13.5AC (bedroom). They will do the job in the summer. We do use insulated reflective material in the windows facing west and/or south depending on trailer orientation along with fans. We started going in the winter because we just didn't like the heat, humidity and the incessant bugs.
My concern with your trailer is the increased size (3' longer and I believe the interior is higher). With two 13.5 ACs I'm afraid you might be really stretched at times trying to stay comfortable. I would definitely go with two 15k units on the unit and you would probably be OK. JMO