West Runton is a lovely beach at low tide - not much space at high tide, get a little tide table or look on the internet before you go. Lots of fab things to do in N Norfolk depend on tide times.
The best beaches in the area (and in the world, to my mind) are Wells, which has miles of wide open space, dunes, pinewoods, a nature walk, a car park, cafe, toilets, trampolining, boating lake, and you can hire one of the magnificent beach huts from Pinewoods Caravan Holiday park (spenny, though). Spend time on the beach, and also walking through the wonderful pinewoods - great tree climbing. Then sit on the quay in the town and have fish and chips from french's chip shop, not the other one.
and
Holkham Beach has fewer facilities, is even bigger and wilder, also has dunes, pinewoods etc.
Further along the coast Brancaster is a lovely beach, the sea is nearer than at Wells.
A ferry trip to see the seals at Blakeney Point is a must, you get really close to millions of seals - the ferries go from Morston, you can book in advance from Blakeney Quay, at the pub in Morston, or google Blakeney Seals ferries and book through Bishops ferries. Time depends on tides, so plan ion advance. Open boats so check weather forecast, too.
Holt - good chi chi shopping and a massive Budgens
Cromer - pier, charming centre, OK beach, small multiplex cinema showing a great selection of films, tiny museum behind the churcg - it is worth visiting the museum before going to w Runton beach because it explains all the fossils and the Hairy Mammoth they found on W Runton.
Sheringham - very charming small seaside town, 'Splah' indoor leisure pool with flumes etc, OK beach, excellent cliff top walk if you head West along the prom out of town, and keep walking straight along the cliffs to Weybourne.
Blakeney is nice - buy a crabbing line and bucket in Spar, bait from the fish shop next door, sit on the quay crabbing, walk out along the sea bank, or down the creekside path beyond the car park. Great paddling and mud slidng at low tide and you can hire canoes on the shallow creek.
The Steam Museum at Thursford is good - traction engines, the old dance hall steam organs (they play them in rotation) and a few steam driven roundabouts that you can go on. (wet weather stuff is a bit harder in N Norfolk!)
Norwich Castle is v good, and the old shopping arcades next to it are lovely.
The Kelling Heath hol park is LOVELY. Nice walks, bike trails, adventure playground and it's own stop on the steam line to Sheringham. I have never camped there - the camping field does look as if the like to cram people in a bit.