"Enjoyable" doesn't mean "empty" but it does mean, for me, not being stuck in queues of cars out in the country. Any chance of that in the middle of May? Particularly on the A39.
Mid May will likely be after the Early May Bank Holiday weekend and before the Late May Bank Holiday.
If you click the link, you will be able to monitor the traffic situation in the area that you plan to visit. (You may need to zoom down & click & drag). The traffic flows on the major routes will be coloured with red indication jams & green showing that everyone is flying along. Now this will be live - at the time you click the click and therefore not at the time that you initially bookmark the link, Of course, you must take into account the time difference. I do not envisage jams in the middle 3 weeks of May.
https://www.google.co.uk/maps/@50.6249902,-4.2051001,10z/data=!5m1!1e1
The roads will be enjoyable, A39 should be fine. I've driven on A39 in June and July and have never be stuck in queues of cars.
Thanks all. Last time I was there was February in 1991. Just wanted to check.