I'm no expert, but I do believe that staying on-site at UO is the way to go since you will be visiting during the peak season. This will, of course, give you unlimited Express Pass access with your hotel keys as well as the hour-early entry to the parks. Plus, the convenience of the walking paths and/or water taxis to and from the parks cannot be beaten.
I've never purchased the meal plan nor do I know about the military discounts, so I'll let someone else speak to those questions. Good luck & have fun!
I have never been to an Orlando theme park in the summer time because of the large crowds, but I have done a lot of research and discussion with people who do, so I think I have some incite.
The dates that you are going are right at the end of summer when families will try to plan one last trip before the kids go back to school, so the parks will be busy. If you can afford the on-site hotels and they are available, that is going to be your best bet. The perks with staying on site are very valuable especially during peak season. The unlimited express pass will pay off big time if the park is busy and not having the headache of traveling through Orlando to the park in the morning will be a big relief as well. The website OrlandoInformer.com has a "crowd prediction" calendar that is good to check and see so you can get an idea of how busy the parks will be and what the park hours are for the days that you are visiting.
If you can't afford an on-site hotel, then I would recommend booking through Universal and stay at a Universal Partner hotel. If you stay at a partner hotel, you will get early access to the park for an hour before the general public which will allow you to get on some of the most popular rides without having to wait forever! You can find the partner hotels on Universal's website in the vacation packages.
I have planned several vacations myself on the Universal Orlando Resort website and it is pretty simple. I stayed at a partner hotel, Westgate Palace, and took their shuttle to the parks. If you need help with the Universal website, you can call their toll-free number and get assistance or an operator can book your trip for you. I don't know about military discounts, so that would be a good question to ask your operator. I usually can find cheaper airfare myself, so I don't book the package with airfare.
I don't know if you are planning on flying or driving, but if you fly and stay on-site or at a partner hotel you could get away without needing a rental car.
Lastly, in my opinion, the meal deal is a waste of time. Unless you are going to eat three full meals in the park each day from the cheap counter service restaurants, you will be better off buying food as you go. Also, most of the partner hotels or the on-site hotels have coupon books that can give you 10-20% off some of the pricier sit-down restaurants so after your discount, you paid only a little bit more for a nicer sit-down meal than the cheap counter service meal.
I do however recommend buying the normal souvenir cups for soda. You can purchase those from restaurants or stands in the parks. I believe they cost $8.99 or so but if you buy 2 you get 1 free and you can bring them back for the rest of your stay. The refills will only cost $.99 after you buy the cups. OrlandoInformer.com is a great resource for getting more info about Universal Orlando and will have a lot of info on booking your trip.
Sorry for the novel, but hope this helps! Have fun on your vacation. I will be there about one month later and I can't wait!
You will find yourself having no trouble leaving one park and going to the other or some of the group heading back to the hotel for a swim while others stay in the parks and ride.
Your waits are essentially zero except for Forbidden Journey, but if you arrive at the gates when they open for on-site guest early entry, you can ride it twice before the park officially opens.
The beautiful part is, you have IOA all to yourself until well after 12 noon because everyone heads for Potter when they open.
You can easily ride everything in both parks multiple times and still be able to stop for lunch and swim for a couple hours.
We stayed across the street once and have stayed on-site every year since then. We are leaving in four days... can't wait.
As a side note: If you stay on-site, you will get some evil glares from people who are waiting in the regular lines as you glide right past them. Be sure to order some inexpensive clear card holder / lanyards off eBay for everybody before you go. I paid 99 each for ours. You can keep your hotel key facing one way, which they will scan on every ride and your park ticket facing the other way so they can scan in as you go from park to park.
They never get lost that way and you don't have to go through your pockets digging them out every time you need them.
Walt Disney World's Magic Kingdom
Disney's Animal Kingdom
Disney's Hollywood Studios
Disney California Adventure
Universal Studios Florida
Universal's Islands of Adventure
Universal Studios Hollywood