I think it will be both cuz remember the cliff hangar in The Остаться в живых Hero? Rick would probably make a flashback in the son of Neptune about where and what happened then Percy was found. Then it will go to present день and it would most likely be both.
It could be about any. The Название suggests it would be about Percy in the roman camp, but Rick might add a bit of Camp Half Blood(I haven't read the summery yet). I was thinking, wouldn't Percy pop up at the Roman camp the same time Jason popped up at CH-B? So, the idea of building the лодка mightn't even excist yet(at the time in the books), so, it mightn't involve the building of the boat?... Just a suggestion?
I think it will tell both. Ты know, like Breaking Dawn, the last Twilight book. It was трещина, сплит into parts, and it was pritty good. I think Rick Rordan has done that kind of book before, but I'm not sure. :)
It is definatelly about Percy at the roman camp! cuz if Ты read of the first chapter of son of neptune Percy wakes up and heads towards the roman camp. then in the секунда chapter he runs into Hera discized as an old lady and she tells him he can eather go to the ocean and let her die или carry her across the river to the roman camp. and in the end Percy chooses 2 go 2 the roman camp. so therefore it would have 2 be about Percy and the other roman demigods. and since the main characters in the Остаться в живых hero were one roman(jason) and two greek(Piper and Leo) demigods, then the son of neptune will be about one greek(Percy) and two roman(Frank and Hazel) demigods.