Hi Kelli,
You are in luck; there is so much to do around
Bay Lake Tower at Disney's Contemporary Resort!
Even though your accommodations may not be ready yet, you can check in when you arrive, get your Key to the World Cards, and have Bell Services store your luggage so that you and your children can go out and have fun. If you give the front desk a cell phone number when you check in, they will be able to text you when your room is ready.
When you check in, you should receive a list of the recreation activities at Bay Lake Tower. Consult this for ideas of things that you can do around the resort. My family and I enjoy spending time at Community Hall. You can play games, color, and relax. There are typically special activities going on at Community Hall, from painting ceramics to making character pillowcases. I know that you already know about swimming, but do check out the recreation guide for daily poolside activities. From playing Goofy Bingo to having a dance party, not all of the poolside activities require getting wet!
You can also head on over to Disney's Contemporary Resort. My husband and daughter love playing at The Game Station, which is the arcade on the fourth floor of the main tower of Disney's Contemporary Resort. You can also head to the Boat Nook Marina and consider renting a water craft for a while.
Finally, it might be fun to take a monorail ride. Hop on the monorail on the fourth floor of Disney's Contemporary Resort and ride around for a while, taking in the sights. If you get on the resort loop of the monorail, you can stop off at Disney's Polynesian Resort or Disney's Grand Floridian Resort and Spa to explore.
I hope that this gives you some ideas for your first day of your vacation, Kelli. Please do not hesitate to ask if you have any further questions!