Walking and Cycling in the Highlands, a new edition of his guidebook, is the product of those expeditions and contains 40 trails which John has dedicated his free weekends to discovering. "You'd have to ask my wife how I get away with it," he laughs. "I get an adrenaline rush from the exercise. I suppose there's a sort of escapism involved as well - just doing wild trips out in the middle of nowhere; the experience of being in a place that's so far from civilisation."
John discovered his passion for the outdoors when he joined the Scouts as a boy, growing up in Bolton, and he moved to the Highlands after university "to be near to the mountains". His book is something of a rallying call to those who may be unaware of how close they are to stunning lochs, forests, beaches and mountains.
"There's a lot to discover and you sometimes have to search it out locally and find out what's on your doorstep. I suppose that's what I do. I've got a map obsession - I always look at maps, see where the paths go," he says. "Each time I go out I discover somewhere new. I see new paths and I think 'I wonder where that goes' and you just see where you could end up."
He says the hobby is accessible to those on a low budget: "Walking is just a matter of sticking your shoes on and getting out there. Even if you don't have a car, you can get on the train with your bike. Not too far from Inverness, you can be in the middle of nowhere."
Fergal MacErlean, who recently finished the fourth in a series of five guide books about cycling in this country, says: "Scotland has some of the best mountain biking - on and off-trail - in the world. And, likewise, for road cyclists, you are spoilt with the scenery and miles of quiet roads. For me, the north west of the country can't be beaten for a road tour. I couldn't choose a single favourite route but anywhere around Applecross or the stretch between Achiltibuie and Lochinver is fantastic".
For John, his forays into the wild, occasionally staying in remote bothies overnight and battling the elements and midges have produced a few highlights. "My trips are all kind of memorable. I finally got myself to Knoydart last weekend and did a couple of Munros with a mountaineering club. We took the boat over from Mallaig and did a bike ride then a walk over the mountains. It was nice just being out there on a Saturday when the weather was great."
For the less accomplished, John recommends the 11.25 mile circuit around Loch Affric, about 25 miles south of Beauly. "If you've got a reasonable level of fitness it's a great way to get out into the hills without actually climbing them," he says. Another of his favourites is the walk to remote Sandwood Bay, beyond Kinlochbervie, Sutherland - a beach where legend has it a mermaid was spotted. "It's quite a drive to get up there but it's worth it - it's a beautiful walk," John says.
With years of experience of the unpredictable Highland weather, John urges his readers to be ready for anything. "You can get some pretty extreme weather conditions. On higher ground it sometimes even snows in the middle of summer, which is why I tend to over-pack my bag. Even if it looks like the weather is going to be glorious, I always bring waterproofs and extra layers."
Fergal agrees. "If there is a downside to cycling in Scotland it's the rain. I'll never forget heading to do a simple, short cycle by Fortingall in Perthshire when I had to battle through 2ft floods. Usually having good waterproofs means rain isn't too much of a problem but not that day!"
Cycle tourism is estimated to be worth £239 million annually to the Scottish economy, and the National Cycle Network (NCN) extends over 2100 miles across Scotland.
Sustrans, a charity dedicated to promoting sustainable travel, says: "Typically, NCN routes follow traffic-free paths, minor or traffic-calmed roads and segregated routes through towns. The routes are often highly scenic, allowing the cyclist to take in breath-taking scenery - lochs, glens, dramatic coastlines. The provision of cycling facilities is continually improving right across Scotland."
For information on national cycle routes, bike hire and cycling holidays in Scotland, see http://www.visitscotland.com/see-do/activities/cycling