Four years ago we set out to The World for our first trip as a family. My DH thought he would hate disney

- I do not even know why in the heck he thought this and to this date neither does he... so he wanted me to plan all kinds of "non-disney" stuff. And just so that he would agree to the trip- I did it. To this day I regret it. We had two days at MK, one at Epcot, and one at Hollywood Studios. We then did Sea World and the Kennedy Space Center plus the Astronaut Hall of fame.
So we had a blast at M.K. and I was happy with what we saw in two days. Covered most of it that we could do and see and the time with a 5 year old and my six month old DD - (yeah we were crazy!!)
One day wasn't enough for Epcot in my mind. We didn't even really spend time in The World Showcase other than to eat burgers at America
On our day to Hollywood Studios (now Disney Studios) it started out a great day and then at about 6:00 the sky opened up and poured so hard we were soaked to our underclothes in two seconds flat. So needless to say we left immediatly. We ate dinner that night at Outback Steakhouse. I was so pissed because we didn't even get to make it far enough into the park to see Rock n Roll Roller Coaster, and I still to this day haven't seen fantasmic.
On our day to Kennedy Space Center my DH surprised me with a 3- hour bus tour. While I got to hold my six month old daughter in my arms in the hot bus... but this is a memory I will not re-live at this moment
And then we come upon our Sea World Day .... we were hot, and tired. It's alot of sitting in the sun and watching... I LOVE Sea World.. let me say that right off. We even went there in San Diego on Honeymoon. But my husband and I noticed right off a huge difference in the people who worked here to the quality of the service at disney. My brother in law even said he thought Shamu had got a lawyer .. (because he didn't do as many big flips) !!!
So anyway one thing we learned is not to combine non-disney with disney. We felt we were comparing the whole time and you just can't compare. Also it only cost a few extra dollars to add a disney day and it cost a lot more to add Sea World.
My suggestion would be to either add the more option and go to Typhoon Lagoon as suggested. Or you could add a day to your ticket and go to one park in the morning and go back and swim at the resort. Then the next day take an easy morning and go back to that same park for the Night event. (fireworks and the such).
And remember that if you are used to a beach bum type vacation that you don't want to get home and feel like you need a vacation after your vacation !! My husband had said we could rest when we got home... and I was ready to lose it by the night of day two... in all the excitement it is so easy to over do it.