Traffic likely to be dire on Saturday on the coast road unless you get here before 0900.
Suggest those coming from or via the home counties suggest you peel off A303 at Andover, down to Salisbury and follow the old A30 to Crewkerne, then B3615 to Lyme. Not fast but pretty and hopefully quieter.
For those of you coming via Hampshire, you could leave the A31 just after Ringwood before you hit the single carriageway bottleneck, take the B3081 across beautiful Cranbourne Chase to reach the A30 at Shaftesbury, then as above.
Hope you get here before it's all over!