I'd suggest working with a real workbench, instead of trying to piece together your own with random objects. You'll find things looks a lot better with real roofs and more detailing objects than with ultra specific things like giant blocky letters.
That kiddie coaster is pretty rock solid. The rest is kind of bland, mostly just too simple. Also get rid of the giant letters, they look bad.
I'd suggest working with a real workbench, instead of trying to piece together your own with random objects. You'll find things looks a lot better with real roofs and more detailing objects than with ultra specific things like giant blocky letters.
That kiddie coaster is pretty rock solid. The rest is kind of bland, mostly just too simple. Also get rid of the giant letters, they look bad.