Hi Dana!
Having had the opportunity to enjoy vacation stays at both Disney's Port Orleans Riverside and Disney's Old Key West, I can say that I loved both resorts and each offer their own unique experience.
Port Orleans--Riverside is one of the popular moderate resorts, boasting southern charm and beautifully landscaped grounds. The Magnolia Bend section offers guests accommodations in mansion type buildings. The Royal Rooms are also available here, for your princess at heart, and are located in the Parterre and Oak mansions.
Old Key West is a deluxe villa resort, and offers guests the opportunity to enjoy the comforts of home, such as full kitchens and washer/dryer (in the one or more bedroom villas). The studios offer two queen beds as well as microwave, compact refrigerator, coffee maker and sink. It is an expansive resort, but wheelchair accessible rooms will keep you close to the hospitality house.
It is a very personal decision as to what resort you want to select, but I would recommend OKW. You'll enjoy the space (390 square feet vs. Port Orleans 314 square feet), as well as the amenities included. The pool area offers entertainment for kids of all ages, so your children will have a blast enjoying the slide and the games offered.
Hope this helps you plan your magical vacation!
-Malanie