You don't sit on the cart by jetting onto them; you get on the vehicle and change the seat you are sitting in.
Once you enter the ferris wheel ticket booth, press . or , to change seats. Also, please remove the quote of the OP - it is unnecessary and stretches the page.
There should be a pack of theme park rides.
Merry Go Rounds with default horses when?
you could make your own with bot events pretty easily