In regard to the elevator situation...you'll quickly learn how slow the elevators are on the Wonder and Magic (they are smaller). The mid-ship elevators are almost ALWAYS busy, overpacked actually so you're better off taking the few extra steps to either the forward or the aft to catch an elevator ride, especially during the busy times like dinner/show time, etc.
The BEST Konk Coolers are at Conched Out bar on Castaway Cay, it comes right from the machine frozen soft serve, get them to float the sucker with the Meyers Dark rum (if you drink alcohol) and you'll be a happy Camper! They will be serving/delivering drinks at Serenity Bay as well, it just takes a little while for them to get down the stretch of the beach.
If you rent snorkel gear, or bring your own, you'll still be required to wear a neon life vest (those are provided at no cost) but you don't have to inflate it. The snorkeling lagoon on the family beach is where the trails of "Exciting" things are. Serenity Bay has no official trail but there is a "shipwreck" out there and there's usually some small to mid-sized fish and gorgeous starfish. I've heard reports of a baby octopus as well but I haven't seen it. The water is VERY clear and bright on Serenity Bay, but there's not always something to see.
There's a few water stations along the paths because of the 5K they do in the mornings, and they sell packs of bottled water you can take off the ship, etc. We've always found it more of a nuisance to carry bottled water with us than to just grab a cup and fill up when we were thirsty. You can also get beverages when the Cookies and Cookies 2 open for lunch (12 to 2).
If you are sensitive to the sun grab a spot with an umbrella b/c the sun can get brutal and you'll want a spot to retreat. A straw hat and cover up are always good and don't forget the sunscreen and to RE APPLY the sunscreen...or by the time you get back to the ship you'll be looking like Sebastian!