as PPs said, rent a car if you're not driving.
we've shopped at the publix, winn-dixie, and super-
walmart nearby - all have decent prices and a nice selection (avoid goodings at the crossroads - very pricey). consider bringing a cooler (or buying a cheap styrofoam one), along with ice packs - to cool items such as drinks (you can add ice from ice machines). the local groceries have lots of prepared foods such as rotisserie chicken, wings, subs, etc. between the fridge, toaster and microwave, b'fast and lunch should be easy.
maybe barbecue at the pool a few nights.
if your villa is near a refillable mug station, it might pay to buy your son a LOS stay mug (LOS will be good at both resorts) - powerades can add up quickly.
check for restaurant groupons in the area (house of blues in DTD, giordanos, etc pop up there occasionally).
in crossroads:
- flippers pizza has pasta & fatbreads are excellent and they have special pricing 11a-4p 7 days a week
- TGIF has daily specials (love their thurs $3 huge appetizers & yummy margaritas)
and quite a few other eateries
use zip-locks (perfect to separate personal items), bag clips, and plastic containers to help organize. assign at least bathroom drawer/cabinet and one dresser drawer to each person. use the closet: hang as much as possible, shoes organized by person on floor, and the top shelf for purchases (or larger "stuff"

).
store carry-ons and anything you won't need in the suitcases, and put suitcases "out of the way" (we usually keep our OL and suitcases by the empty entry).
bring/buy laundry pods (and dryer sheets if you use them), and get to the laundry room before 8am - there can be a wait otherwise (we get ready, and time our returns to 5-10 minutes before our washer/dryer should be done). our dirty clothes go into a large, lightweight duffle each day, then we just carry it to the laundry room. it gets washed along with the clothes. delicates get hung on the laundry line in the bathroom. our laundry supplies are stored under the kitchen sink.
while we've never had more than 2 in a studio, i can honestly say we've never felt cramped or as if we're missing out on something (we've stayed in 1 and 2-bdrms with more ppl).