-Err...Very miniscule spoilers for LAst book-
Hades and the Olympians hate eachother less at the last book of the series.
I dont' exactly remember what terms they were at, but Percy requests it.
The Percy being the owner would be a nice idea
-End miniscule-
-Spoilers-
Maybe Dionysus could be pardoned by Zeus for his fighting and.."death"(For lack of a better word) during the fight with Typhon.
Personally, I'd like a war of Immortals sort of thing (Maybe Olympus gettign divided, Or Titans, etc) that would be like the big battle in the final book-Where Camp Halfblood has to guard certain landmarks and negotiate with humans/demigods/Minor-Gods of good/evil.
EX:
Lotus H&C: Time is slowed down here, and Human money can be obtained here in mass amounts. (I dont' like the movie version of it though..) A good safehouse because supplies would never expire, etc etc. Only the Most Sane can be in there, though.
Gate to the UnderWorld: If Hades attacks, then switch with the Mount Tamapais. If Titans attack, then Self-Explanatory.
Empire State Building: Olympus. Self-explanatory.
Mount Tamapais (Mount Orthys): See Gate to the Underworld.
Hoover Dam: Statues to Zeus.
Gila Claw, Arizona: The Junk of the Gods is important-even if its just junk to the Gods. To Minor Gods/Demigods....
Miami, Florida: Base of Operations for the Party Ponies and Launching point to Sea Of Monsters.
Smithsonian Museum, D.C. : Den of Nemean Lions.
Camp Half-Blood: Self Explanatory.