There is a lot of Scotland that isn’t remote islands, @NewStartFamily - some places that are really remote, some that are bustling inner city, and everything in between.
We have never regretted moving from Essex to near Glasgow - we live in a village within an easy drive of countryside, city and coast. There are good transport links, good schools, good hospitals, and plenty for kids to do - my dses did so many different things - hockey, drama, musicals, choir, cricket, BMX style biking, off road cycling and even tractor appreciation with the Young Farmers.
Where we are is probably more urban than you are looking for, but I would encourage you to look at different areas of Scotland, not just the islands. I am sure you can find the balance between the rural escape you are looking for and somewhere that still allows you fairly easy access to a social life and services for you and your son.
As I said in my post earlier on this thread, I would be very careful about how isolated you choose to be - as a kid, my parents moved us to a very remote, tiny village, where dsis and I were complete outsiders, and that really damaged my mental health. Honestly, after a decade living there, I could count the number of friends I had on the fingers of one hand - not for want of trying.