Two seniors - Should we buy Octopus Card or what ?

Oct 29, 2016 Shenzhen North arrival around 2 pm by train from Guilin
Go to Futian Check point by subway line 4
Walk to Lok Ma Chu and catch East line MTR to Hung Hom
Walk to subway station Tsi Sha Tisu station for hotel stay
Oct 30,2016 Local site visit
Oct 31, 2016 Ferry to Macau and return
Nov 1, 2016 Hong Kong island
Nov 2, 2016 Fly to Chiang Mai Thailand
Subway line 4 - one travel from
East Rail - one travel from Lok Ma Chu to Hung Hom
Return trip to Macau to Kowloon
Airport express or bus – one travel from Kowloon to HKIA
Bus or subway trips to see local sites