Hi. I've been in Adelaide for over 17years, so I know it pretty well. I'm originally from West Yorkshire, and I hadn't visited before either.
If you want to live near the beach, I would recommend go south of the city for value for money. Housing is very expensive (though it may fall) so further south the better. I've lived all over Adelaide, and I'm now in O'Sullivan Beach. It's a bit rough-hence the private school. But is on the improve. Lots of poms like Hallet Cove- they call it Little Britain. Port Noarlunga is nice, and Moana and Aldinga are lovely. Consider Christies Beach. It is up and coming.
As long as you avoid the Northern suburbs especially Elizabeth, Davoren Park, Salisbury you should be OK.
Also depending on your budget/suburb/values you might want to consider private schools. Private schools are quite a big thing here. I've put 3 kids through the state system. And I've got 1 in a private school, and I wish I'd have sent them all private- but that's just my experience. There are a lot of great state schools, but they are usually zoned.
There is a southern soccer league that plays at O'Sullivan Beach. And a junior league too.
Lots of employment opportunities.
Can't advise on the campervan. Sorry.
Best of luck.
Janine