Bath to Tingagel

The most important factor is when will you be visiting? In the summer and during bank holidays and Easter you could experience heavy traffic which could double the journey time.

It is certainly doable. I haven't checked it but I'd be surprised if you could do it in much under 3 hours. The motorway only takes you to Exeter and then you're on A-roads and smaller and at the mercy of traffic, especially if trying to get round Exeter in the rush hour. If the house opens in time, either do it early or late.

Is it doable! In short I'd probably say no, depending on the time of year and whether you mind arriving in the dark. The roads south of Bath are awful, single lane and twisty and easy to get stuck behind a lorry. You won't average more than 40mph. From Montacute over to the M5 motorway will be more of the same. Once you reach the motorway itself that's usually ok unless you are hitting a peak holiday time. You'll come off the 3 lane motorway and then will hit the A30 Devon expressway. Don't be fooled by the name this route is also not that fast! You'll end up with single carriageway stretches again before you hit Tintagel, and if you're going in anything approaching summer months expect plenty of caravans along the route! I'm not sure if there is a particular reason for wanting to stop there. If you just want a Stately Home, Castle Drogo would be right on your route. Or head north out of Bath back towards the M4 and you'll pass Dyrham Park. Both nice National Trust properties.

opps! Forgot that important fact, our trip is set for the 2nd week of September.Thanks for reminding me.
I love Tudor and Elizabethan history.

That's a great time of year to visit :)
It will still be relatively light in the evenings. Depending on how long you want to stay to look round I'd say yes you could do it but allow yourself 3 hours to get to your destination once leaving Yeovil just to be on the safe side (it shouldn't take quite that long) Perhaps try and leave Bath a little earlier?

Ps when I say awful roads, you'll pass through some lovely countryside and the roads are perfectly drivable, but you just can't pick up much speed.

Thank all for ,as usual, great advice!!

We were there in late September and left Bath around 10 a.m. and got to Tintagel between 5:30 and 6. On the way, we spent some time in Wells to see the Cathedral and have lunch then drove through Cheddar Gorge. It was a lot of driving, but was doable.