Hi Bob,
Thanks for visiting the Disney Parks Moms Panel with your question. The good news is that Walt Disney World has so many wonderful resorts from which to choose. My family and I really like exploring all of the different resorts.
Of the three that you listed, my favorite resort and recommendation for you would be
Disney's BoardWalk Inn. The attached Disney's BoardWalk Villas are my home resort with Disney Vacation Club, and I love it there! There is so much to do within walking distance around Crescent Lake. You can get to so much recreation and dining without ever having to use any other transportation other than walking. You can even walk to Epcot and Disney's Hollywood Studios, or, if you prefer, take a boat ride to either. My family really likes Luna Park Pool, the pool at Disney's BoardWalk Inn. It has a really fun waterslide, the Keister Coaster.
My next choice of the resorts that you suggest would be
Disney's Caribbean Beach Resort. The theme is fun and tropical. If either of your children are interested in pirates, you might consider booking one of the Pirate Rooms there, which are themed to pirates and include beds that are shaped like ships! Of the three that you listed,
Disney's Saratoga Springs Resort & Spa would be my last choice recommendation for you. While the resort is lovely, the theme might not be exciting for your little ones.
I hope that this gives you some ideas for your vacation, Bob! Have a wonderful time planning, and please do not hesitate to ask if you have any further questions.