I love the Royal Princess! I sailed on her in 1986 then again in 2002 and found that Princess was keeping her in great shape! I would sail on her again in a minute!
I just got off the Carnival Glory (brand new ship) and must report during certain maneuvers, all ships vibrate!!! :-) If you sit in an aft dining room when they are pulling away from the dock, the ship vibrates, no way to stop it!!!
She is an absolute classic, I found the food to be right on par with other cruise lines and I've sailed with 6 different lines on many types of cruises, 7 days or longer! In fact both my cruises on the RP were long, 12 and 15 days.
As far as being claustrophobic, I didn't think that at all because public areas/lounges have lots of windows. Alot of newer ships have no open areas, not even by the pools, everything is enclosed.
I'd say go for it!