From Glasgow:

Follow signs for A82. Turn right at Tarbet. Continue to Crianlarich. Turn right at the first roundabout you come to directing you into the village of Crianlarich. Continue to the T junction by the Crianlarich Hotel. Turn right onto the A84 signposted Killin/Stirling. 1.5 miles outside of the village you will find Portnellan on the right hand side.

From Edinburgh:

Follow signs for M90 Stiirling. Exit at junction 10 for Crianlarich. Continue on A84/A85 towards Crianlarich. Portnellan is situated 1.5miles before the village on the left hand side