Usually with a power chair you need a van with a ramp, and some way to get the chair into the van. Then you need to figure out if you want to drive from the chair (the driver's seat is removeable), or if you want to transfer from the chair to the driver's seat. If you want to transfer, then a different configuration is necessary to make that happen.
The vans that accommodate power chairs are low to the ground, so you have to have clearance from the road to the van. If you're in the city, or driving mainly on paved roads, there isn't a problem. But if you're in the country (like I am), driving on dirt or gravel, the low van means you "bottom out" all the time -- hit the road with the bottom of the van, not a good thing!
Or there are structures you can buy that hook on to the back of the car, like "boat hitches", that you'd drive your chair onto, and strap it down. But then you'd need to be able to get to the front of your car on your own "power" (like, with crutches or walker). And the chair is out there in the rain, snow, whatever other elements, getting dirty and dented from road debris. I know they'll try to offer you covers, which help, but that is a consideration.
The scooters are easy to take apart and re-assemble, but still heavy, especially the battery part. So you'd need to be sure you could even lift that into the car. And then make sure that all the parts will fit!
Don't expect a LOT of help from the car company. Usually you have to have applied for that when you bought the car..and it's only around $1,000 anyway. I don't know what the MS Society may offer.
If I were in your situation, I'd probably go with a scooter, for now (I'd consider the 4 wheel kind, though; they're much more stable). You can always move to a power chair later.
...I am not a doctor, nor health professional, and don't pretend to be one, here.....