Don't know how far "too long is" but going South gives you good options too.
About 10 miles: Norwich > Trowse > Stoke Holy Cross (turn left up Stoke Road*) > Poringland > Arminghall > Trowse > Norwich
About 20 miles: Norwich > Trowse > Stoke Holy Cross (left after the Church) > Shotesham > Brooke** > Bergh Apton > Poringland > Arminghall > Trowse > Norwich.
** Or turn left on the Norwich road to cut out the Bergh Apton part and shave a few miles off.
Or longer still, don't turn off in Stoke and keep going to Saxlingham, Hempnall, Woodton, Seething, Mundham, Brooke then as above. Around 35 miles.