We've only flown space A for one trip--it was back in 1998 and we took space A from Okinawa to Tokyo. We were fortunate and didn't have a problem getting the flights we wanted--but at that time there were several flights taking that route each day, and there were only two of us.
The flight from Okinawa to Tokyo was on a C9 modified for medical passengers--basically a regular airplane but TONS of extra leg room! It was awesome!
The flight from Tokyo to Okinawa... well first I should mention that though we did get on, there were several people who arrived after us that did not get on. We also met a woman (dependent spouse) and her 3 children in the terminal who told us she and her kids had been trying to catch a flight back to Misawa (I think?) for a couple days, and hadn't been able to get space!
When we got on the plane, it was a C-130. We sat in what was essentially net "hammock" things...it was loud, they handed out earplugs before the flight. The flight took about twice as long as the Okinawa to Tokyo because of the type of plane. And, there was no bathroom. They explained to us they had a bucket behind a curtain for us to use. The AF personnel explaining it asked the gentlemen to please try to refrain from using it if at all possible and to save it for the ladies...but that didn't happen. I don't know too much about "the bucket behind the curtain" because I didn't even try to use it--I can't even bring myself to use a porta potty so even though I had to go badly, I just held it!
If you don't have a ton of time to wait for flights, I would only chance it if you are ok with paying for a regular, commercial flight at the last minute so that you/wife/daughter can get back if needed.