...Walt Disney World with Kids. It suggested not spending any one day in one park - too much walking, too much watching, etc. if you stay in one place. Do you agree?
Pretty much. We like to start our first three days with Disney Studios or Animal Kingdom in the mornings, and end those days with Epcot (open later, great fireworks and after Magic Kingdom, the younger one may want to return to MK when spending a lot of time at Epcot). On our 4th day, we go to Magic Kingdom and if the noise level and sun are getting to me in the heat of the afternoon, we switch to any of the other parks with a promise to return to MK the following morning.
If you are all enjoying the park that you've chosen for the morning, just stay - be flexible.
Even when we stay offsite, we do usually enjoy an afternoon rest or swim, if the parks are open until at least 8PM. If we run all day for a couple of days, we plan at least one day of rest mid-week (sleep in, late character breakfast at a Disney resort, swim all afternoon or visit a water park, early bedtime).
The afternoon rest breaks do provide an easy time to transition from one park to another though. So remember that whatever time you would have spent in park-hopping can be deducted from the time you spend returning to your condo to rest.
When park-hopping, just drive from one park's parking lot to the other - leave your day's parking pass in the car, since it's good at any Disney parking lot all day long. You only pay once per day.
BTW, with a 5 year old, do take him to see
Muppet 3D at Disney Studios BEFORE you visit
Honey, I Shrunk...3D at Epcot. Muppet is more benign. When my 5yo twin DSs saw Honey first (and found it scary), later they didn't want to wear the 3D glasses at Muppet.
If your 5yo is adventurous and tall enough, he will be able to enjoy almost everything his older sisters can enjoy. Ours did! Exceptions may include:
MK - Alien Encounter and perhaps Splash
DS - Rock N Roller and perhaps Tower of Terror
And don't let the preteens and young teen convince you that they are too old or too cool for attractions like Little Mermaid, Muppets 3D, Country Bear Jamboree or Dinosaur. The special effects and fun presentations can easily make some "less cool" attractions into fast favorites, even for adults.
I also don't know what to see first and how.
When you look at the park maps (are they in that guidebook?), note which attractions offer FastPass in each park. This tells you immediately which are the most popular attractions. Head straight for these early in the mornings and do them first (no FastPass if standby wait time is under 25 minutes or use FastPass if it's over 30 minutes).
Along the way, you'll see that there are other attractions that you will want to return to later, when time allows or when you're waiting for a FastPass window. Choosing a list of a half dozen must-sees (as a family) ahead of time will help you a great deal. Make use of each park's chalk board near the center front of the park, that offers the current wait times for each main attraction, to judge where to go next if you are stumped.
We like to start out with these attractions:
AK - always Kilimanjaro Safari, then Dinosaur or Kali River
MK - once, start with Dumbo and Fantasyland and once, start with Splash/Big Thunder, then Space
DS - Rock N Roller and Tower of Terror
Epcot - always Test Track, as the FastPass fills up early in the day
Bring a change of underwear/shorts/socks for everyone and leave them in the car. It's hot in July but they'll get soaked if you all want and somehow those items don't dry out easily, can cause blisters or chafing.
Also, I checked with our condominium and in order to get out it would probably be a stiff penalty. I really wish we could take advantage of all the benefits of staying on sight- especially early entrance days.
There have been no regular Early Entry days (only isolated, high attendance exceptions) since late 2001. So don't feel you are missing anything with that. MK is still reportedly crowded on Saturdays so try to avoid it then, except to see the evening light parade and fireworks (park hop - it's worth it!).
Note where we've stayed on our Disney trips (in my sig - plenty of both - onsite & offsite). You will have a lovely first visit to Disney! I personally think that you are likely to spend much more time at the parks on a first visit than a repeat visitor would. So it's wise to stay wherever you can afford and not overpay for a Disney resort (in most cases) on a first time visit. JMHO. You will also enjoy and appreciate the added space and quiet of a condo, especially when you want your youngest to rest.
The kitchen will enable you to provide easy, filling, favorite breakfasts inexpensively to start your days. If you take a midday break, you may even find that you can just have an early snacky lunch at the parks, from the carts or quick counter service, then an early kid-friendly (microwavable or pasta) supper in the condo with dessert at the parks later too. This can save a lot over a week! Make use of your freezer by freezing juiceboxes and 3/4-filled water bottles each night - top them off with water before taking them to the parks in the mornings.
where do you think the best place to purchase tickets is?
If you are using the AAA discount, buy them ahead of time at the AAA travel center near you. If you will use the Disney Card, buy them through there or at any Disney counter (like the one in Downtown Disney - no parking fee).
do you recommend a character breakfast, or is it just a waste?
On a first visit, it's a great ice-breaker. It can also take up a LOT of valuable ride-time when lines are usually shortest (meal times), if you do one when in the parks. We liked the character breakfasts at Wilderness Lodge, Grand Floridian and the Poly - fun to see these resorts too. And the dinners at Grand Floridian and the Contemp were great buffets. One of these would be great on the evening you arrive in Orlando, if you don't plan to visit the theme parks that day. We've enjoyed an early dinner buffet with the characters (before 6PM), then took monorail rides to Epcot. By the time we got back to our resort, it was after 9PM and everyone was happily excited to start our vacation at WDW! Enjoy!