WordNet sense 1 (have smooth relations):

get along with, get along, get on with

WordNet sense 2 (get on board of (trains, buses, ships, aircraft, etc.)):

board

WordNet sense 3 (get on the back of):

bestride, mount, hop on, climb on, jump on, mount up

WordNet sense 4 (appear in a show, on T.V. or radio):

be on

WordNet sense 5 (develop in a positive way):

advance, progress, progress, come on, come along

WordNet sense 6 (grow old or older):

age, maturate, mature, senesce