There's a well-known and quite large site near Dawlish Warren that has a lot to recommend it. It's called Lady's Mile, its pretty cheap IIRC but it has excellent facilities, on-site shops, pool, gym etc. It's walking distance to 'The Warren' for a great beach, also not far from Dawlish town for the quaint Devon seaside experience. Cream teas, more pubs, decent chips, bakeries etc. Then, the next town along is Teignmouth, which is a really nice place to spend days and evenings. And there's a regular, direct bus too if you want to err stay up late
It is kid-friendly but the site is large so you can easily find a quiet spot. Also if schools are back, there'll be a lot fewer about anyway. And dogs are welcome IIRC.
There's a smaller, wilder, less 'infrastructured' site near Newton Abbot I've heard nice things about, called Tucketts Farm. It's really picturesque and the nearest beach is the Ness beach at Shaldon, which is another really nice one. They also make their own cider - but, I'm not sure they're dog friendly.
/South Devon promotion