I have used my personal ECV several times when taking the tour. It is three-wheel with a very tight turning circle. I never had a problem with it and I was never asked to transfer to a wheelchair.
Thanks Cheshire Figment. I rent from Randy's and I don't know the model but it turns on a dime so maybe I'll see about adding on the tour. I--as opposed to my too coll for their own good teenagers--really enjoyed that boat ride throught he "farm".
I had a three-wheel Amiga from Randy's last time, and I'm not sure it would have been AS easy to maneuver through Behind the Seeds as the ECV I'd rented from Scooterama the year before (when I did the BtS tour) but you should be fine.