I think everyone is different on this one. My husband and I have a terrible time getting a scooter out of a deep trunk even if it's broken down. The base piece is awkward for us. We can do it, but it's time consuming and very tiring for us. We've done it as a two some all the time. We are on the shorter side which may be why it's harder for us. I will say if you can get by with one of the smallest portable scooters it is easier. Scooters are weight dependent and some scooters are only good for people under 200 pounds. If above that weight limit then you get a slightly bigger and heavier scooter which is harder to get in and out of a trunk.
If you have a local scooter company you can go look at the portable scooters and most of the time they will teach you how to break it apart and they will let you put it in and out of your car trunk. This way you can get a feel for the situation. Considering you may buy a scooter in the future I don't feel bad using up the store's time for this purpose. The Pride to Go is a popular scooter model that's sold and rented.