An Caisteal

An Caisteal sits above Arrochar like a proper Highland sentinel, though technically you're still in the Lowlands - the landscape hasn't quite made up its mind which side of the fault line it belongs to. The walk up is steep and relentless, a genuine hill rather than a gentle stroll, taking most people between 45 minutes to an hour depending on fitness and how many times you stop to catch your breath.

From the summit, you get views across Loch Long that justify the grunt, especially on clearer days when you can see the Arrochar Alps properly laid out. The peak itself is rocky and windswept, not a place to linger if the weather turns, but brilliant for that moment when you've crested the ridge and your lungs remember how to work again.

This appeals to hill walkers more than casual visitors - your average tourist after a half-hour amble will find the ascent punishing. Families with older kids (10+) who don't mind a proper challenge will get something real from it, but don't bring the five-year-old expecting an easy time. The whole outing takes about two hours round-trip, so it's a solid morning or early afternoon activity.

Beinglas Campsite sits just down the road and makes a solid base if you're tackling a few peaks in the area. It's free to climb, naturally - Scottish access rights and all that. The best time is May through September when the path isn't waterlogged and visibility is more reliable.