Our backyard is rather small, about 80' wide and 20' deep
in the center 35' or so we play to have patio for outdoor dining and entertaining, on the one side about 30' we plan to have some plant.

And on the other side about 15' x 20', right outside of the kitchen window, we plan to make it a small play area for our toddler.

What would be a good idea
- play structure. but they're usually much bigger. is there some compact ones?
- sand box. our girl loves sand but someone just said that cats and animals might come and do some business. yikes. plus, sands always gets everywhere, even our car is full of sand despite all shaking and patting
- trampoline. how long would kids love it?

and what kind of surface would be kid and wallet friendly and low maintenance? mulch, shredded rubber, artificial grass, grass...?

thanks for your suggestions