Any free or cheap children's outside playground stuff. A tetter totter. Logs. Just not close to the fence because they can jump like ninjas. Some are jumpers and some are crawlers so fence has to be totally secure in all areas.
The house is fine for two goats. Just always consider the jumping goats that won't stay confined. I have a Doe that can clear 6 foot fences without a problem. Barking dogs are an issue till they get used to the barking. Lots of play things to jump on and play are needed because a bored goat gets...