Hello Highland Connection,
That's a good post !!! If you are enthusiastic, you can walk almost everywhere and then with some training you can walk the rest : places with more difficulties.
Walking is the easiest sport. You don't really need to get seriously fit before. You just need to walk regularly but starting with short and easy walks first. Then little by little longer and harder walks and you'll realize you'll get fitter very soon.
A friend of mine keeps saying : "Hillwalking is good for the mind and for the body, it should be refunded by the Social Security". He's right !!!
The only investment you need to do is to buy a good pair of walking boots and waterproofs. But that's it !!! If you join a group of people, a hillwalking or rambling club you'll find people who will take you to the hills.
That's what I did when I lived one year in Inverness in Scotland. I joined two hillwalking clubs and every weekend I was on the hills. In winter, skiing on Saturdays in the Cairngorms and hillwalking on Sundays. That was the best way I could discover this wonderful country : Alba.
I hope that soon you are going to post about some of your walks Highland Connection.