We've stayed at the Wilderness & Kalahari. I like them both for different reasons. You can get great deals at the Wilderness and they have several different waterparks, but you walk alot which is a pain if you have small children. They also have, lasertag, a big arcade & an indoor playground for when you need a break from the water. At the Kalahari you have one big waterpark indoor & one big one outdoor. It's easier to keep track of everyone especially if you go as a group, plus they have the water coaster & the surf machine (can't remember the name). When we were there, they had baby tigers in the lobby, tattoos, & karaoke. They both have several family activities within the resort as well. I'm not a fan of most of the restaurants at either resort, with the exception of The Fields at the Wilderness. They have great food, but it is a little more high-end restaurant. The buffet at the restaurant in the Wilderness is really bad!
As far as activities, the Ducks tours are great, I think it is the Upper tour that we like better--the one where you get out and see the dog jump the cliff. Also, the Tommy Bartlett Water show has always been a crowd pleaser, but I'm not sure what's going on with the lake right now (last year the dam broke & the lake was drained). All of those little side attractions--wild life park, upside down white house, etc. aren't really worth it. In the summer, it can be a pain to get downtown, but there are a few decent restaurants--Famous Daves & there's one that overlooks the water. Closer to the Wilderness & Kalahari there's Moosejaw, which is ok, not great. They do have sampling trays of the microbrews that you can order and the food is decent. There's also Culver's which is a great, inexpensive alternative--fast food, but something for everyone. Stay away from Damon's at the Kalahari though. The food is terrible, as well as the service.
There is a Walmart off of the last Dells exit on the west side of the highway and a grocery store as you go into town. I suggest buying cereal & other easy breakfast stuff, bottled water & other drinks, snacks, bread & lunch meat. Eat breakfast in the room, bring snacks to the parks, go back to the room for lunch and back to the parks or on your excursions. Then you only have to go out for dinner. All of the rooms have microwaves. The Wilderness has some nice in-resort condos that have full kitchens. The food service counters at the resorts are crazy
expensive--we spent $24 on 3 donuts, OJ, coffee & oatmeal.
The waterparks are slowest right around 5ish 'cuz most people take a break from the long day & go to dinner. If you can't tell, we go every year and the kids keep asking to go back. You'll find that the kids are perfectly happy not even leaving the resort (during the winter, we never do), which is good because if you go beyond what's offered at the resort you can find yourself spending a great deal of $$.
I hope this helps. Have a great time & a HUGE thanks to your brother for his dedicated service and our freedom!!!