First off, a good double stroller is a necessity with twins (or 3 kids under 5 for that matter). We've taken 2 different ones. The first time with the twins, we took our Joovy Scooter X2. It's a great stroller and has the biggest basket of any double stroller on the market. We can fit 2 full backpacks, baby carriers for babywearing in the parks, and a few lightweight jackets in the bottom. The seats recline fully, which is great for napping. The canopy cannot be beat in terms of its coverage. Honestly, it's huge. While we loved having these features, there were 2 downsides: (1) no cup holders for mom and dad or children. Okay, this is only semi-accurate. There are mesh pockets for the children. And there are 2 small mesh cup holders for adults. However, this is not sufficient for our drink needs. Coincidentally, there's no child trays offered for this stroller. Major bummer. And (2), maneuverability sucks. Not even kidding. There were times, especially when my 4-year-old and larger twin were in the stroller together that it felt like I was going to dump the whole thing.
The second trip we've taken with all 3 kids so far, we've taken our Schwinn turisimo double jogger. Maneuverability, cup holders, and child trays exist (though the child tray is kind of far from the seat for smaller children). We also found a great rain cover that fits nicely over it, which was a bonus in the rain. Unfortunately, it's larger, heavy, does not recline quite as fully, and has a much, much smaller basket. We were able to shove the baby carriers and jackets in the bottom, but had to cut back to one backpack and hang it from the parent cup holder console or wear it. Still, between the two, I recommend a jogger (and riding in one of the 2 designated rows of the Mickey and Friends tram that allow you to leave the stroller open as it won't fit in the narrow aisles even folded). You can rent a stroller, of course, especially if you're traveling by airplane, but honestly, it's easier just to have your own in my experience.
We do purchase most food in the parks. You aren't suppose to bring snacks in, but our older son has severe food allergies and my twins are young enough to require specialized foods. I don't think the CMs would ask even if you have older kids, though. Anyway, we purchase lunch, dinner (if we're there that late), 1 snack (usually churros or Dole whips), and a soda or 2. Breakfast, eaten on the drive down, is usually a bagel and cream cheese for everyone 3 and over and a fruit and cereal pouch for the 1-year-olds.
Below is a list of our most common items to bring. These are typically placed in 1 or 2 backpacks, though we try to shoot for only 1 as it's easier to manage:
- sunscreen
- diapers (calculate 1 for every 3-4 hours, plus an extra for poop per child)
- wipes
- changing pad
- lightweight jacket
- hats
- change of clothes for each child including underwear and socks (my babies always lose their shoes and/or socks at Disneyland)
- blankets (usually left in the basket area since they're bulky)
- baby carriers (usually left in basket area, again due to bulk; we use Infantino Flip Front 2 Back carriers--we don't wear any time except in the parks, so these are a great value. Do not crotch dangle until your babies are old enough though or you can hurt their hips. For younger babies, Ergo is easier, but more expensive. Plus, CMs prefer and often require baby to face outward if worn on rides.)
- tissues
- 1 burp cloth/old style cloth diaper for cleaning up messes
- sippy cups for the twins
- medicines
- benadryl and epipen for peanut allergy child
- infant tylenol
- gas-x
- dramamine
- Advil
- sinus spray
- snacks
- 2 juice boxes for older son
- 2 chocolate milks for older son
- chips or crackers
- baby puffs
- graham crackers
- frozen tubes of go-gurt
- 2 water bottles (can be refilled and shared)
- umbrella (only when raining)
- stroller cover (only when raining)
- stroller fans (only when over 85 degrees)
- cooling bandanas (only when over 85 degrees)
- mist bottle (only when over 85 degrees)