I agree with doing 'trial runs' in local stores. A few years ago I used those for about 4 months after I shattered my ankle and even though it'd been awhile, the 'memory' came back when we used an ECV at WDW.
We used bandannas (cheap n cheerful tied to the baskets to make ours easier to find. Just don't use something expensive or that is obtrusive or that will block another person's view and/or be a hassle going through the queues. So, don't tie balloons or anything that would stick out or up too far. And don't leave things it the baskets when you park the ECV. Yes, it's Disney, but people will still be people.
They aren't that hard to maneuver, really. The CM will give you the spiel when you pick it up. They're really slow, people walking a normal 'Disney pace' (you know, that 'quick walk' we all do) were passing us. They don't have a brake, it's all controlled with the little lever on the handle. Push, you go. Release, you slow or stop. And they stop pretty fast when you release and go just as quickly when you press it. If it's not too crowded when you get there, just take a little time to try out its paces and get familiar with start, stop, and the turn ratio.
Just give yourself plenty of room in front and look around when you want to make a turn and accept the fact that you aren't going to be the first in line for anything, lol. I didn't have a problem NOT smacking into people from behind or into them when I turned. And if someone stepped into my path a quick release of the handle stopped me right away. I never had someone smack into me from behind when I had to make a sudden stop, but that would have been their problem for 'tailgating', lol. No one ever said anything to me, so I must have done OK. Just remember it's like driving a car, look before you move, give the person in front of you space, etc etc.
The main 'problem' I had was navigating the queues. Those turns in the 'back and forths' are really tight and sometimes I had to make 3 (or 4 or 5) point turns to get round the corners. But since we're talking DL here, there aren't going to be that many queues that you'll be taking an ECV through. Again, just take your time and don't get rattled if you hold up the queue a bit navigating the corners.
You'll be fine. I fought using one for years, but after the difference in my Disney Day at WDW, I think I'll be using one most of the time from now on. Or at least on my 'bad days'.
