Hi Laura,
Thanks for asking us a question!
There are lots of character dining locations throughout Walt Disney World, you can see a list of them by clicking
HERE and then choosing character dining under the drop down list dining experience. Which one you choose really depends on which characters your children like. My girls are aged 11 and 12 and their favourite places to eat are the Crystal Palace in the Magic Kingdom with Winnie the Pooh and friends. Dinner at 1900 Park fare at the Grand Floridian with Cinderella and her family, my girls just love how funny the ugly step-sisters are and laugh throughout the whole meal. Garden Grill in Epcot with Mickey, Pluto, Chip & Dale, they enjoy the food here and the fact that the restaurant rotates through part of the ride The Land. Breakfast with Lilo & Stitch at 'Ohana and if you have Princess lovers then I would suggest Akershus Royal Banquet Hall in Epcot but if you have fussy eaters only eat breakfast here as lunch and dinner is Norwegian food.
I'm afraid that Port Orleans Riverside does not have a business centre, these are located at Coronado Springs, Contemporary, Boardwalk, Grand Floridian and the Yacht club. But depending on what you need your front desk might be able to help. For example they'll often allow you to check in for your return flights online and print off your boarding passes. Each resort is different and things do change but it's always worth asking!
Have a great trip,
Jo