The Central Station and Queen Street Station have trains which whisk you off to various spots and bring you back at the end of the day. Buchanan Street Bus Station also provides transportation to various points of interest. If you're on a budget, the bus is usually cheaper than the train. But check out rail passes, they might be something that would fit into your schedule and finances. Nothing can beat exploring by car, for you can stop anywhere you want as you meander your way along winding roads and discover hidden lochs and valleys.
Car rental does tend to be expensive, as is petrol.
The trips coming up I took by train. Cheap day returns are the most economical and trains are plentiful. If you're worried about the weather, that's good. Off we go to Loch Lomond, Gourock, Edinburgh and Stirling. We will begin our virtual tour at the Glasgow Central Station.