Bring an extension cord that you can leave plugged in so you don't have to reach a wall outlet every time you need to charge. Consider a second cord of you need to charge in the parks.
Let's make that a HEAVY DUTY cord - many standard extension cords can't handle the current required to charge an
ECV. Some manufacturer's do say to not use an extension cord at all; the manufacturer of my personal scooters has no such restriction, so I carry a heavy duty extension cord for each of my chargers (I have a charger for each of my batteries). If you charge your battery fully overnight, every night, you will most likely be able to go all day at WDW with no problems!
Be sure to put the Rental Vendor's contact information in your phone, including office hours, and after-hours emergency information (what to do/who to call if your unit fails after regular office hours). Having that info at your fingertips will help save you a lot of stress if you need it! (And you most likely won't!)
Since you are traveling alone, you may want to have any purchases you make at the Parks either sent to the front of the Park, or back to your room, so that you don't have to worry about carrying everything around by yourself all day.
Bring along a length of brightly colored ribbon, or a brightly colored bandana to tie on your rental
scooter. That way, if a CM does move your scooter, it is easier to find.
When you get your rental (I'm assuming you are renting an ECV from an outside vendor) take 15 minutes or so at the Resort to learn all of it's features, and get a good feel for how it handles. Take the time to practice driving up and down sloped/ramp areas. See how tightly you can (or can't!) turn, and get used to backing up. Practice at the Resort driving through shops & QS locations to get used to those types of venues - at the Resorts is a great place to practice your new skills because it will be less crowded than the Parks or Disney Springs!
When it's time to drive on the bus, just let the driver know that you are traveling alone, and let him/her know if you will need any assistance with the ECV for loading/unloading. If you have time in your schedule, a "practice run" to Disney Springs is a great way to get used to not only the ECV but loading/unloading from buses and even boats (if you use the Water Taxis)
If it helps, many folks carry along a walker or a folding cane on the ECV; you can use bungee cords or Velcro One Wrap to strap the walker to the back of the ECV seat.
Using the door stop is a great suggestion - if you can, once the door is "stopped" open, "walk" the ECV through (or use the slowest "Turtle" speed you can) because Resort room doors are one place where a lot of folks get frustrated. You didn't say which Resort type you will be staying at; Values & Mods all open outside to the sidewalk, and so have the higher doorsill you will have to "bump" over every time. Deluxes (with their interior hallways) have relatively flat doorsills by comparison, and so are easier to manage.
I hope you have a lovely time!
