The heaviest part of a disassembled Pride Go Go ECV weights about 42 lbs. The maximum weight for checked luggage, most airlines, is 50 pounds. A case of water can weight 40 lbs. Valet and Bellhops are compensated with tips. You do the math.
You want an empty trunk. Goldmobility says don't stack the pieces. Rearranging the pieces around other stuff is a PITA. Make sure your luggage can fit in the back seat or let Disney transfer your luggage. Gold has great videos on their site. Watch it. Skip the rear basket.
My, limited experience going from PBH to Dolphin. I was using a car service. I started to disassemble the scooter. A bellhop came over to take over before I even got the seat off. He brought over another bellhop so he could show him how it's done. The driver told a bellhop, as we were pulling up to the Dolphin that we have a scooter. The scooter was assembled as fast as it was unloaded. The person assembling it was showing a couple of other bellhops how it's done.
I bought an I-Go scooter and brought it last trip. I used Lyft XL. Bell services had me show them how the scooter is taken apart and folded.
Conclusion. You'll be 100% Ok if you can disassemble the scooter. Loading the pieces in your trunk is not that much different then loading luggage. I think there is at least a 99% chance a bellhop, or fellow guest, will help you disassemble it. Watch the video. Have it bookmarked on your phone.
Worse case scenario. Have Disney ship your luggage. Leave your car at CSR. At some point in your trip take a Lyyft no scooter, from the Contemporary to CSR. Drive back to the Contemporary. Make sure you valet your car. If that's no possible have the Lyft driver take you to your car, assuming the distance isn't walkable.