>>2523273You can go pretty much everywhere up to the central Highlands by train from Glasgow.
Loch Lomond area and Arrochar Alps are only a short train journey, and there are trailheads right at the trainstations where you get off.
For example there is several good hikes from Arrochar & tarbert station.
Alternatively you could get the train to Corrour station, which is Britain's most remote train station, from which you can hike to loch ossian or loch trieg, and camp there, before getting the train back next day. Or climb one of the nearby Munro's.
Or you can do a thru-hike from Corrour to fort William and get the train back to Glasgow from fort William, but this hike will take a couple of days. And make sure you're prepared for the conditions. The weather up there can get deadly and it's very changeable.
