I wish I had the room for such a plan! It sounds like you are on the right track. Keep it simple and think like a kid! Something to crawl through, like those flexible tubes that dogs run through, something to jump! and things to climb up and over. The rope is a great idea for climbing, not many gyms have those anymore. LOL... you could dig a mud hole and fill it with water! :-)
Good luck! and post pics when you are done!