Congratulations! Being an ex HGV driver and now courier driver I travelled across UK several times
. I can highly recommend couple of driving trips:
1. Snowdonia , hours of picturesque drives there, especially roads like A4212, A470, A487, A4086, B4406 actually anywhere within Snowdonia National Park you go is beautiful. Whilst there I highly recommend taking an extra 45min and driving towards Porthmadog (nice small town) and than is only a stone throw to Morfa Bychan where you can take a Beach Road which leads straight to the... beach! Beautiful sandy, flat and wide which you can actually drive on or stop for a sunset for example.
2. Cornwall! (it should actually be number one
. Small camper van like T6 its ideal for narrow roads and also plenty of camper van friendly places there. Driving to Cornwall just stay away of the A30 and anywhere will be beautiful (use it on a return journey).
3. If you love piece and quiet I recommend Isle of Man, love the empty roads during the day!
There's so many nice places! Other places worth visit are Devon south coast, Dorset coast, White Cliffs of Dover and than scenic drive to Brighton, Lake District National Park, Peak District National Park and of course Scotland, ( beautiful Loch Lomond lake just outside Glasgow if you in the area ), Brecon Beacons National Park.
That's it for now...