That thing is huge. Your grandkid will love it, your kids are not. But I fully support the direction this is going.
Also, I've got a few winch cable Zipline too. I forget where I buy the trolleys from, but got some stainless parts up there that I leave on year round. Pro tip you can use a winch snatch block in a pinch and there's enough resistance in it that it keeps the zip adventure a bit more tame for the first week or so.
