Longest for currently and old for Go North East of my head are

Current
1-Whitley Bay to Metrocentre Asda
78 Consett to Sunderland
35 and 35A Boldon to Low Moorsley
10A Newcastle to Blackhall Mill
16B Durham to Consett

Old I'd say
1/1A/1B Whitley Bay to Metrocentre or Kibblesworth or Wrekenton
42A Kingston Park to North Shields
17 Cramlington to Whitley Bay
42 Cramlington to North Shields
X40/41/42/43/44/45 Newcastle to Blyth or Morpeth or Thropton or Pegswood