At 60yrs old, I would like to buy my first decent motor vehicle. It is for touring and carrying grand children. I am 6.00 foot tall and suffer from back problems. I have therefore, been looking at Nissan X Trail and Ford S Max. This will be my first and last purchase of a vehicle so i have to take into consideration cost of parts and maintenance etc. I wouldn't be using it everyday so i don't know which would be better petrol or diesel. I would appreciate any help or suggestions of other vehicles as I don't know anything about motor vehicles.