I've ridden this route in the past and the West side has some spectacular views where the East side has a more challenging route. However, weather can be variable - when it is clear this will be a great run, when it's wet and especially if it is windy, it could be miserable! Keep your eye on the weather forecast!
You can do this run in a single day from West Central Scotland (I have), but travelling from further afield, it would be worth staying in Inveraray for couple of nights and spending a day doing the route. Details of accommodation here. Nearby campsites here. Note: I haven't stayed at any of the places on these websites, so can't give any opinions on them.
Alternatively, you could split your journey with an overnight stay near Campbeltown. Accommodation: here, camping at Machrihanish: here. Again, I've not stayed in any of the places on these websites.
More information: here, here, and a leaflet from Argyll and Bute Council (including a map) here.
If anyone rides this route, please post comments below.