There is a great path along much of the coast.
Some good stretches:
Cromer to Overstrand (there are also buses between Overstrand for the trip back)
Sheringham to Weybourne - cliff top, pub and cafe in Weybourne
Round the sea bank Cley to Blakeney
Blakeney to Morston
Morston to Stiffkey… and Stiffkey to Wells
Wells to Holkham (fantastic, beach, woods, )
There are also inland walks up onto Salthouse Heath and Kelling Heath
This coast is a mix of vast stretches of salt marsh, freshwater marsh, shingle and sand beaches, low sandstone cliffs and heath, interspersed with lovely villages.
A few buses a day go from Sheringham to Felbrigg Hall , which has a lovely long walking route round it, as well as the Hall . https://www.nationaltrust.org.uk/visit/norfolk/felbrigg-hall-gardens-and-estate
Holkham Hall is also an interesting visit, Hall, walk round the lake and deer park.
There is a bus to Holt, a lovely small town.
And to Binham with its priory ruins
Bus map:
www.sanderscoaches.com/timetables