If that 1778 Dunfermline one is the correct Robert Donaldson then you can see it's not far to Carnock where he and Jane Campbell had the kids.
Also there is a death on SP for a Robert Donaldson , correct age , at Falkirk (connected on map).
DONALDSON
ROBERT
80
-----
M
1858
479 / 2 / 85
Falkirk Landward
He had been a farm servant... because it's after 1855 the record should be quite informative as far as parents/occupation/spouse etc. Worth having a closer look.