DisneySea is probably my favorite Disney park (I’ve been to FL, CA, HK, and Tokyo - just need Shanghai and Paris), if only because of the immaculate attention to detail. There’s so much to just LOOK at. And it’s a great overall theme. If you can afford it, absolutely stay at MiraCosta (though we did a split stay between the
Disneyland Hotel in a Beauty & Beast themed room and MiraCosta in a Venice room overlooking the canals in the park). I also recommend splurging on the package that gives you Fastpasses - lines are LONG, even with Fastpasses. Also, don’t look online for anything about the Journey to the Center of the Earth ride. Not knowing what to expect is part of the thrill of the ride. We used two of our Fastpasses to ride it twice.
Happy to answer any questions you might have! It’s an amazing park and I wish I could go again!