Does it have to be South Devon? We’ve been to Woolacombe Bay on the North Devon coast (just down the road from Ilfracombe) a couple of times and really enjoyed it.
The set up is a complex of 3 or 4 holiday parks, you choose which one you want to stay on but your price gives you free access to all the other parks, with a cheap bus (about £1 for a day I think) that will shuttle you between them and also to and from Woolacombe town itself. There’s plenty to do on the parks (organised kiddy clubs during the day and discos at night, swimming pools, crazy golf, bingo/music in the evening for the adults etc), but also the peace and quiet option you mentioned.
The accommodation ranges from caravans to chalets and, on the main park, a huge great farmhouse (4 bedroom I think) with a decent kitchen, washer and dryer, it’s own private garden, hot tub and BBQ – this is where we stayed last year and loved it.
Woolacombe itself is fairly small but has the usual cafés and gift shops etc, plus a massive sandy beach. There is a bus service as I mentioned earlier, but you can walk down from the main (Woolacombe Bay) park in about 15 or 20 minutes. Alternatively, you have Ilfracombe about 15 minutes drive away and Barnstaple about 30-40 minutes away.
As a reasonably priced UK holiday, I can’t recommend it highly enough, we’ve been for the past two years running and would be going again this year if we did not have a house move to fund.
Here’s a link
http://www.woolacombe.co.uk/