Yes, you can. When the main A83 is closed, there are 3 other routes you can take:
Convoy - During daylight hours, a vehicle convoy will run on the 'Old Military Road' adjacent to the main A83. follow the usual route through Tarbet and Arrochar.
Ferry- Increased service on the Gourock-Dunoon crossing during road closures. Turn right onto the A815 through Strachur & St Catherine's before taking a right on to Hells Glen (B839). We have discounted family tickets on sale at Reception and/or tickets are available from the newsagent on Shore St, next to the Co-op.
Diversion - Turn right at Tarbet and take the A82 to Tyndrum. Join the A85 to Dalmally, then the A819 to Inveraray. Then take a left onto the A83, following through to the other side of the 'Rest'.