If you sign up for Romance Rewards, you can do a Trading Places day on Monday, Wednesday, or Friday. You need to sign up with Guest Services 24 hours before you want to trade. The resort provides transportation--you leave around 10am and they bring you back around 4pm. If you want to come back early, you pay the cost of the taxi. Trading Places is a free perk for Romance Rewards members.
If you sign up for Romance Rewards you can do the Trading Places between the two resorts and see CSS for a day. We highly recommend doing this if you're thinking of returning and want to see another Couples Resort. Also, by signing up for Romance Rewards, you'll be able to get additional perks on future visits.