We haven't checked luggage since the airline lost our luggage on our honeymoon 17 years ago ! We were at WDW in May for 8 days and our family (Me (40) DH (43) DS (10) and DS (5)) travelled with 3 small wheeled carryons. I had a very small purse - big enough for tickets, passports, wallet and tylenol. DH carried the small camera bag and DSs had a small backpack with a book for everyone, their puzzle books, a favorite stuffed animal each and their electronic games. We do not do laundry while we're on vacation. I am very low maintenance - I wash my hair in the shower in the morning, throw it into a ponytail and go - no hairdryers etc for me ! Basically, it's all in the packing. I stack outfits for the boys - shorts, shirt, undies and socks - roll them up together as tight as I can, stuff them in the bottom of a gallon sized zipper bag. I can get about 2 days worth into a bag for each of them. Then, I suck the air out of the bag - vaccuum works well, or a straw, zip it shut and toss it in the bag.
We wear our running shoes on the plane and pack a light pair of sandals. Swimsuits and jammies take up very little room. We even had room for souvies ! It can be done, it just takes a little planning !
It's also very freeing to grab your bag at MCO, head to car rentals and be in the parking lot before others even have their bags at baggage claim !