driving in Devon/Cornwall and amount of time

The main roads are OK, but the coastal villages can have narrow roads, so care is required, but thousands a year manage.

Three full days is just about enough time to allow for some stopping en route and a return to Bath.

There are two Bank Holidays in May - the first and last weekend and this area will have much more traffic over this time.

Do you mean Exmoor not Exford?

Thank you. Yes, I did mean Exmoor National Park. Thanks for catching that. Unfortunately, our dates would either be May 28, 29 and 30 or May 27, 28 and 29 depending on how long we spend in the Cotswolds. Perhaps we should aim for the 28-30 dates to avoid most of the holiday traffic.

I'd go further than Jennifer and say the main roads are fine and so are the majority of the minor roads too. You will come aross some narrow lanes with high hedges, but they aren't too diificult. Just take it slowly. I rather like roads like that. On Dartmoor, and to a lesser extent Exmoor, you quite often find even the narrow lanes are open and you can see anything coming the other way for miles.

I spent some time in Cornwall last month, traveling by train and bus. Some of the buses running along coastal routes are double-deckers. I remember thinking it was nice to be on the upper deck of those buses because you could see over fences and hedges. I have no idea what percentage of the time you'll be seeing nothing but a wall of stone or green if you drive, however.

One thing to keep in mind about the small coastal towns is that when they're busy--don't know whether this could apply to May--you often need dinner reservations even for restaurants that seem very ordinary. It's not just the very fanciest places that fill up. But perhaps May is early enough that the issue will not crop up.

I had a lot of trouble finding affordable lodgings, looking just a few days in advance, even away from the coast. Again, May may not be a problem.

Due to budget constraints many English towns no longer nave tourist offices, though if you ask around (this can waste a lot of time), you may find somewhere you can get a map of the town. More than any other country I've visited, you really need to have done your research ahead of time. A "tourist information point" may be marked with the standard "i" sign, but it will be nothing but a rack of brochures, plus a town map. (This ismthe case in Brighton, of all places.) The maps are decent, once you find a source. Expect to pay £1 for a map or town brochure if you do find a staffed tourist office.

I don't know whether you will hit the village of Mevagissey on the southern coast. It's fairly near the Eden Project and the Lost Gardens of Heligan. Mevagissey is quite a toursity place but has not one ATM. Some of the local businesses will give you some cash back if you use a debit card.

The roads are no worse than Ireland although they are busier. The problems start when the driving stops - parking can be a nightmare. Clovelly is a private estate and cars are not permitted, it has a parking area above the village and you walk down. Port Isaac is a tiny place, about half a mile long and narrower by width, it had an official car park near the sea which used to be fine but since the Doc Martin crowds another has been opened at the edge of the village on the B3267 road from the south. Make sure you have a supply of coins for the machines (£1's and silver coins usually). Tintagel has more experience and is better provided. As with everywhere in UK, yellow lines along the edge of the road mean parking is banned.

As long as you understand that this would just be a driving tour with short stops of 20mins to 2 hours then 3 days is fine. But the holiday is Monday 28th (all british holidays are Mondays except christmas, new year and good friday). Naturally the traffic builds up from Friday afternoon. Your idea of arriving 28th would be OK since you would be travelling in the opposite direction to the main flow and by evening it would be much quieter. But the rest of the week is a school break in most areas of England so the hotels and B&Bs could still be busy.

Thank you all so much. You have eased my mind regarding driving. However, we don't want to rush our time there. For example, we want to walk down to Clovelly, take the walking tour of Port Isaac, etc., as well as getting out and perhaps doing some walking in Exmoor and Dartmoor. Therefore, now I'm thinking we should spend a fourth night. After that, we have two nights left before flying out of Heathrow. We could possibly spend one night in the Salisbury area and see Stonehenge and then go on to WIndsor to spend the last night. (We had hoped to see Highclere Castle, but perhaps that won't be possible.
Back to Exmoor and Dartmoor - Has anyone done something there that you would highly recommend, maybe even something you discovered that isn't in the guidebooks?

On the north side of Dartmoor is the last water powered foundry in England - National Trust's Finch Foundry. https://www.nationaltrust.org.uk/finch-foundry?PlaceMapClick=130 I had a lovely time there - I really enjoy seeing things being made. It was almost as magic as seeing bells founded much further north well beyond the southwest.

Why don’t you simply look at Google maps and zoom down on the areas you are thinking of visiting and then grab the yellow man and drag/drop on the roads to see what they are like? (You could also click for satellite view).https://www.google.co.uk/maps/@50.8067201,-3.9881202,10z/data=!5m1!1e1

Oh, this is fantastic! I didn't know you could do that with the satellite map. Thanks!
Also, I realized we can have the greater part of four days in the area. (After the third night, we can spend most of the day before heading to our B & B near Stonehenge.) Now the question is whether to stay in three different places along our route, or stay in one place and travel out from there. I know most guidebooks says to try and stay in one place longer, but, in this case, it seems like we'd be doing a lot of backtracking if we did that. What would you all suggest?

I drove in Dartmoor in 2013. I don't understand the apprehension about narrow roads, not criticizing you for mentioning it, just in general I have not had any trouble with this. I did not find the roads in England or Ireland to be especially narrow at all, but we had a compact car in both countries (maybe a mid-sized car in England). We did get stuck in a big traffic jam in Exeter. Dartmoor was a huge highlight of our England trip. When I found out they had wild ponies I just had to go there, and was not disappointed. You can climb up on the big rocks and it is just a very unique landscape. Be aware it rains a lot there, our server at the restaurant in our B&B said the couple of days we were there were the only days they had not had rain in a long while. I think three nights for Devon and Cornwall both is short, I could have spent three nights in Devon alone (we only had two).

When I found out they had wild ponies I just had to go there

If you like the idea of wild ponies then the New Forest National Park is a great place to visit. There are wild ponies throughout the park as well as free ranging cows and pigs (although these are owned by farmers they have ancient rights that allow them to free range). The weather is also a lot more forgiving than Dartmoor.

http://www.newforestnpa.gov.uk

The only suggestions I would make when driving in Cornwall---

1) Be courteous. At times, you may have to back up to let someone else pass. And since tour buses do take the smaller roads, it's best to give right of way.

2) Many of the "hedges" you see on the sides of the road are covering up stone walls. Don't back up into them or you could cause damage to your car.

I was in that area in late May of this year. Traffic was only bad going from Cornwall to Bath on a Friday.

Deciding between hub-and-spoke and a series of one-nignt stays can be a diffiicult decision. Don't forget that if you go the one-nighters route, you'll be driving around with all your luggage in the car most of the time. It is impossible to reduce the risk of theft to zero. I'd spend some quality time with viamichelin.com, recording its driving-time estimates (which people say tend to be optimistic) for possible travel legs. Then think about how much time you may spend packing up and later unpacking every day.

The southern parts of Cornwall also have many attractive places to visit including Fowey, Polperro and The Eden Project. In west Cornwall, St.Ives is very attractive and the Minac Theatre cut into the cliffs west of Mousehole is worth a look if that far west.https://www.visitcornwall.com

When going back east to Stonehenge, you will probably be on the A303. You may wish to take a slight detour to visit:> https://www.nationaltrust.org.uk/montacute-house
https://www.nationaltrust.org.uk/stourhead

Thanks again to all of you for taking the time to share your stories and advice. I really appreciate it.