Hi there
My mom and I have done this for the last 3 trips down to Florida. The first 2, we did the dolphin encounter, the last one, we did the day at Discovery, without dolphin swim.
In our minds, it is completely worth it. We really enjoy the day there. And make a full day of it by getting there when it opens and leaving when it closes.
You don't necessarily have to make reservations weeks in advance, it just depends on the time you are going. If you are going during a high demand time for them, then yes, you need to make reservations, sometimes months in advance. BUT, when we went, we only made a reservation a week and a half prior. It really does depend on when you go.
No, not every family gets a cabana. You have to pay extra for those. And they are not cheap. But they do come with some great perks. I would guess depending on how big your family is, would make it worth it. For my mom and me, not worth it.
You do get to change your date once without penalty. So, I guess if the weather wasn't looking good, then you could change the date. I don't know what would happen if the DAY you went, it was raining. They can still do much of their stuff in the rain, snorkelling, dolphin swim, so Im thinking they are still open. In the case of thunder/lightening, I would assume a rain date. BUT, you would have to call to confirm.
To me, it's a beautiful place. Quiet. A wonderful haven to relax for a day. You are fed all day long, with snacks and drinks included. When you think of the fact that you are getting a park ticket to Sea World AND Aquatica, for use for 14 days......plus Discovery Cove, to me the $259 isn't so bad. I know it sounds like so much but break it down.....$75 if you want to do Sea World for a day, and $45 if you want to do Aquatica for day...makes Discovery Cove $139. Not bad. Considering you get 2 full meals, drinks, snacks, dolphin swim, and a park that is capped off at so many people.
Ultimately it will be what you think is worth it. I loved it!! And will be going back again. I love the day. Good luck deciding