Considering the ages of your children and WDW marketing research identifing children prefer to spend the majority of their time at the Magic Kingdom, I would suggest either the CR Tower (wings are good too) or the Polynesian Resort.
These two resorts out of the three monorail resorts cater to children better than the GF. GF is very good and offer some special kid programs like Wonderland Tea Party, Pirate Cruise, but I think the other two monorail resorts do it a little better with overall kid oriented activities and settings that I think are more conducive to children. I believe Disney know this to and this is why they offer these two kid programs only at the GF along with a few other minor activities too.
The CR and PR all provide easy transportation options and a wide variety of dining options too. The PR also has the only childcare facility in the area which also is the highest rated one in WDW and children tend to enjoy the adventurous atmosphere of the PR. Kids tend to also love volcano pool too. The PR also offer easy access to the transporation center allowing quick access to the Epcot Monorail line. Great castle views at night, Electric Light Parade on the lagoon and easy viewing of Wishes from the beach. Assorted beach and water recreation activities.
The CR provides a easy 5-8 minute walk to the Magic Kingdom and is ideal on those late nights when the monorail line is long. I will note that you can not walk to the Magic Kingdom from either the PR or the GF. There is a walkway between the GF and PR that make for a very nice nightime stroll to visit either resort at night for a nightime dessert or drink.
The main concourse of the CR also provides it's own level of excitement along with its distinct decor departing from it's orginal design. Chef Mickey's at your door step along with the great dining experience of the California Grill. Great castle views at night, Electric Light Parade on the lagoon and easy viewing of Wishes from the CR observation area or the CG if you are dining there at the time of the show. Assorted beach and water recreation activities.
These are also the two original resorts when WDW opened in the early 1970's, so they are not as new as some other deluxe resorts, but the rooms are slightly larger because of this too. You can also dine very easily at any of the three monorail resorts or take a quick monorail ride over to Epcot area (Chef Mickeys (CM), 1900 Park Fare (CM), Ohana, 'Ohana Polynesian Character Breakfast, Kona Cafe, California Grill, Citricos, GF Cafe, NARCOOSSEE'S, Victoria and Albert's, Garden View Lounge Afternoon Tea-Grand Floridian, Wonderland Tea Party (GF), Pirate Cruise (GF), Spirit of Aloha Polynesian Luau, Tambu Lounge, etc).