Jo
It's a great part of the UK to visit, two years ago we stayed at Dunstan Hill (C&CC site) just 10 or so miles North of Alnwick.
Dunstan Hill is a grass only site with C&CC standard toilet blocks - and takes non-members.
Good points:
Easy walk to the beach - it's a coastal site
Loads of castles on the coast
Holy Island - and the very touristy village
Farne Islands - fantastic for birds at the right time of the year
Alnwick - interesting castle, market in town, and the biggest second hand bookshop in the UK in the old railway station
Great beaches for just plain old walking
Great seaside pubs in small villages with excellent food and beer.
Durham Cathedral is worth a visit - we lived in York and although the Minster dwarfs Durham - it's a beautiful red sandstone
Bad Points:
Weather can be interesting, but with global warming should be hot and sunny
RAF sometimes run training flights over this whole region of the coast - different area, different day - even if you don't like jets it's at most a minor nuisance in the afternoon one day a week.
Robert