Wide roads, easy access coastal sites

Pembrey Country Park is a nice site with easy access and access to a huge beach. We live in Cheshire as well and it's not too big a haul to get down there

Best advice is to take your time. In narrow situations keep well to the side and let the rest sort themselves out.

I unwittingly chose a site in Porlock for our first caravan trip, we survived it so don't be put off by the prospect of narrow lanes etc. Near Porlock is the Minehead site, access is easy and the roads in are ok, nice place too. 

If I were you Mama I would leave the Devon and Cornwall sites until you are really confident. It’s not just the site entrances, we have seen many caravan drivers having real difficulty when taking the wrong turning or a road that they thought was ok. We had to sit with one lady passenger while she calmed down when her husband took a road that he thought was ok and ended up in country lanes, his wife was distraught, we eventually helped them out. A friend visiting recently shouted, while in our car, when a car came the other way on one of our quieter roads, she thought it was one way! We still giggle about it with her.

Narrow lanes are not too much of a problem if there are suitable passing places, the real concern is when passing places are none existent or too short.

Where we live narrow lanes are a way of life but if it's a concern it's probably not worth the worry. We visited a CL in our motorhome a few weeks ago which required a lengthy maze like narrow laned  drive on the approach. The owners had sent detailed instructions with photos, we remarked how difficult it would be towing a caravan...when we got there a big fifth wheeler was  on site, the owners said it was fine getting there! Everything depends on your level of confidence so the OP is being sensible but may find that confidence improves.

When \i first started towing I had no qualms. At 28 I had a young man's confidence 

Thanks everyone, super advice.  Great to have a good steer when starting to plan our adventures. 

Northumberland shouldn’t pose too many problems. Lovely Sites all over. You just need to check out your route using a small scale map to get an indication of road sizes, either paper or digital. Cornwall and Devon are a bit more challenging, but there are thousands doing it, so you will be fine.

Have you thought of Norfolk, pretty good access to the three main site.

David