My wife has MS and uses a wheelchair and scooter. It's a balance between size of car and size of scooter, the smaller scooters will fit easily in the back of car or SUV but they are rubbish off road due to being relatively unstable. The bigger 8mph road legal scooters will go over a fairly uneven ground and deal with inclines but short of having a van or pickup with no (or a high truck man type top) you have no chance of getting it in.
we eventually went for a batec, looks like the front end of a motorbike which fitsj to a standard wheelchairs, it's awesome. You can get it in the boot of something like a ford S Max without any disassembly, the chair one side and the batec next to it. Put some mountain bike type wheels on the chair (readily available) and it will cope pretty decently off road (forestry tracks/gradients/dry grass etc). The only down side is that as the drive unit is in the front wheel, it does lose out on traction. But for ease of stowage, portability etc it is great. Most mobility Scooters aren't allowed on trains, we got approval from norther rail that the batec was as it is effectively a standard wheelchair and a piece of luggage, I can't show you pictures of my wife's as she has travelled by train from the dales to Bradford today, something she wouldn't have been able to do before we bought it.
the trampers are more capable offroad and if you can ride straight from home, definately worth a look. You can try before you buy too, Google "tramper trails" as many parks and visitor attractions now hire them out to visitors.
the ultimate is definately the terrain hopper, but at over £12k it's out of our price bracket for now.
do check out the batec though, from a mobility and ease of stowage/loading perspective it has made a huge change to both my wife and my day to day getting around.
