Hey Barbara! Great to hear from you again!
The Contemporary is just gorgeous & the rooms are simply my favorite in Disney World.
I spotted restrooms in the Lobby & on the 2nd floor where the ballrooms are located. I never ventured onto the 3rd floor. The 4th floor is where Chef Mickey's, Gift Shops & access to the Monorail are found, & strangely enough, I don't recall a restroom on this level. That doesn't mean that there isn't one however!
The 15th floor is where you will find the fabulous California Grill & there is a great restroom there.
If you get a chance to dine at the California Grill, I highly recommend it for the food & the lovely view of the Magic Kingdom's fireworks in the evening.
After answering your question yesterday, I remembered that right before my 1st trip to Europe in my early twenties, my beautiful Granny sat me down & told me that she wanted to share her most important traveling tip with me. I was excited as I look up to Granny (even if she is only about 5ft tall!) & considered her wise & worldly...but then, Granny looks me in the eye & says seriously, "make sure you always know where the restrooms are wherever you go!". I was dumbfounded back then & blinked like an owl at her! But you know what...Granny was right, it is important! Maybe I'm gaining a bit of that wisdom from dear Granny!