Summer Bay is a longer drive if you are planning to visit the Disney or Universal Parks. And you will most likely be dealing with a lot of heavy traffic on that drive. I've looked at that resort and have heard good things about it but have yet to stay there.
This is the information I send to people from up North who come to Florida in the summer rainy season months:
Fact: May-November is the rainy season in Florida and August and September are the worst months for the heat and humidity. It is probably going to rain at some point during the days you are at Disney World so be prepared. When I say rain, I don't mean sprinkle or sun shower, I mean RAIN! It usually doesn't last more than 20-30 minutes but it can really rain hard. And just because it has already rained once don't think that you are done for the day; it frequently rains several times a day! Take a back pack, tote or purse with a rain poncho, a small collapsible umbrella and flip flops in a separate plastic bag if you are wearing shoes/sneakers. Even a small child can take/wear a small child sized back pack with these items. When it starts looking like it is going to rain any minute, put your flip flops on so your shoes don't get soaked. No one wants to walk around in wet shoes for the rest of the day or get blisters from their wet shoes. Wear shorts, no one cares what your legs look like! If you wear pants or jeans they will be soaked from the knees down even if you have an umbrella or poncho as the rain splashes when it rains hard. Your clothes and shoes will stay wet longer than you think as this isn't the dry season. The plastic bag will come in handy to put the wet flip flops in or your shoes if you get them soaked when you go on a water ride.
The Florida summer sun is brutal. You don't want to be the idiot with a beet red face who is about to or actually does collapse from heat or sun stroke! Make sure you bring and wear hats and use sunscreen. Leave your black/dark clothes at home, bring lightweight, loose fitting, light colored clothes. Tip: Put bottles of water in the freezer. Wrap them in paper towels or a wash cloth so they don't get everything in your backpack or bag wet when they thaw. You will have cold water throughout the day and can use the damp paper towels or wash cloth to wipe off your hands and face. If you get overheated or just want to cool off, hold the cold bottle against your pulse points, your neck and wrists. Take at least one bottle of water that isn't frozen so you have something to drink right away and make very sure everyone drinks plenty of water. Too much sun without a hat, being overheated, not enough water, all of these will give a person a killer headache. Don't let yourself get to that point because you will be totally wiped out and about the only thing you can do is lie down for a couple of hours. Another reason to bring a small umbrella, you will see people walking around using those small lightweight umbrellas to shade themselves from the sun and it really, really helps!
When we are at the Parks in the warmer months we invariably have people asking us where we bought our ice cold water. Sorry we brought it with us. It just kills me when I see whole families each with their own bottle of water purchased in the park and they throw them out 2/3 full because the water quickly gets warm. I can think of better/more fun things to spend my money on than paying the prices they get at the Parks for bottles of water, sunscreen, hats, rain ponchos, small collapsible umbrellas, flip flops and backpacks/bags. When you are at the Parks you may hear people who came unprepared and are complaining about the prices they had to pay for the things they needed and could have brought with them if they had been smart! If you are flying and trying to keep the weight down on your checked bags you can always buy what you need at Walmart, Walgreens, Publix. etc. once you get to Orlando. If you are flying in and won't be renting a car, many people take a cab or Uber to the closest store to stock up on what they need for the week. However if you are traveling as a family a rental car quickly pays for itself if just eat one meal a day at a restaurant off the Disney properties or in your unit.
When you visit the Parks you can bring our own sandwiches, cheese sticks, fruit, granola bars, snacks, cookies, candy, etc. and water. I find that it helps the time waiting in line for rides or shows to start go much faster for our now 5 year old granddaughter and me too if I have food/snacks/treats for her. When we stop to actually eat lunch I will have my whole lunch finished and she has eaten a quarter of her sandwich. No problem, no aggravation, when I'm done we leave and I bring out the food to let her finish eating while we wait for the rides or shows.