Scan with the ADS at every jump .... you will get paid plenty and you can do it all in your own time. The problem with passenger missions is:
(a) you will have to find one that you want to take the required distance;
(b) you don't want (or need) a jittery passenger on board that will give you trouble;
(c) you don't need a deadline to complete such a mission.
Just go, keep flying in a straight line for 5000 lyrs, and go an extra few (just to make sure). The trip will be over before you know it.
Alternatively, head out along the chain of space ports that have been set up on the route to Colonia. They are at strategic locations in "nice" places and you can repair your ship at them before returning.