Replying to Backyard non sketchy scketch up.

Ok so i wanna build a not-so-sketchy sketch up. i wanna build a backyard park. i want a sturdy drop in, i want a good box/ rail, i want some other features that are easy to build and fun as fuck to hit.

btw i live in Illinois so its about as flat as the plywood you find at home depot.

Im looking for what materials i need, cost of those materials, and possibly any pictures of some drop ins, some rails/ boxes, and any other backyard features yall got.

i plan on building this next summer and plan on using it for the winter so i dont need turf or carpet or any of that.

lets get this shit started! Enlighten me guys!!!