Forget it! Rode down today and it's there are road works everywhere starting at West Lavington then every couple of miles. Even on the bike it was a pain in the ass.
I then moved onto Poole and it was even worse! I estimate there must've been at least 3 miles of solid traffic. God knows what it'll be like at the weekend.
I took the route through warminster back from Poole and it was fine.