Hi josephsteve, welcome to CruiseReviews! My suggestion is a cruise, too
Hawaii from LA immediately jumps into my mind. You said you like history and classical music, so a Med cruise would fit that bill. There is also a lot of history in the Caribbean, not much classical music though. I would also recommend a reputable travel agent, there are so many choices. It would sound like Cunard would be a good fit for you, but there are plenty of other lines.
Congratulations on your 40th, please let us know what you decide!