This is an exceptionally long road trip. I was on a similar one some years ago but it was about 10 days. It took about 3 days to drive from one end of Sarawak to the other at a minimum speed of 100km/hr, stopping for no red lights (got police outriders). And double the time if you make courtesy call stops.
Once in a lifetime adventure because I 11/10 will not do again. π