I have had extensive experience with using a
ECV for both of my in-laws. Having said that, it has now been about 3 years since they have both come to Disney with us.
Having said that, these were my observations. Please keep in mind, we had two scooters almost all of the times we did this.
Biggest issues were the bus. No issues with the monorail. Some of the boats cannot handle scooters, so they would need to then send a larger boat. This was specifically the case when we stayed at Wilderness Lodge. Again, a few years ago, so things may have changed.
No bus could handle more than two ECV. My MIL could not steer the unit on the bus, so I would often be the one to take her unit on and off the bus. People would sometimes ask questions, or make statements. My answer was always the same. “My 70+ year old in-laws cannot do all the walking. They can walk short distances. My MIL is also a menace on the road, so I drive her ECV onto the bus and park it.”
Having said that, we would often need to split up. In those cases, I would send my father in law with the entire family, and I would wait for the next bus. This was one thing when heading back to the hotel. However, when heading out, not much we could do.
I have never found a cast member who could really help us out with the buses. Then again, they may have been working behind the scenes and just not wanted to promise us anything as they may not know exactly when the next bus would arrive. Not faulting them, just stating the facts.
We too would rent scooters, and I do remember them being about $125 for the week. That was thru Apple
Scooter and again several years ago. Looks today like their rate is $30 a day, with a 20% discount for 7 or more days. So I guess that comes out to about $170 for a week now. Either way, it is way more economical than $70 a day at the parks. I have also discovered there are times when the parks run out of
ECVs. Again, a few years ago, so perhaps not an issue now. Also, you have the unit with you so it can be used outside the parks as well.