When our kids were little we got them a wire bead rollercoaster, something like: https://www.ebay.com/itm/304637213979

It's one piece. Cleanup is picking it up and putting it where you want it. For playability, that thing kept each of our kids occupied for an unreasonable portion of their toddler-hood. We then passed it on to friends, and it did the same for their kids. They kept it, and gave it back to our kids when they had kids, and it's still delivering joy.