Not quite the Sahara, but my Son and two friends recently took part in an event that involved driving from Lille to Barcelona in a car that was purchased for £300.
He bought a 'T' reg SAAB 93, with damaged paintwork, 100+K on the clock, and no MOT. It did have some service history, but nothing recent.
After replacing one front tyre with a second hand one, it passed the MOT with no advisories. Before they set off, he did no more than check the fluid levels.
He opted to take the most difficult route over the Alps, and along with other participants had to stop to allow the brakes to cool on the descent. Much of that 16-hour day was spent in second gear.
After arrival in Barcelona, it was going so well that they decided to drive back.
They did 3,000 miles in five days, and the return journey of 980 miles was completed in 15 hours, which included a delay of one and a half hours for the train. It sat at between 90 and 100 mph for much of that time (resulting in at least one speeding ticket!).
It literally didn't miss a beat. Even the oil level didn't drop. Sadly, because it only had one day's insurance left, the following day it was scrapped.
I would have been seriously impressed if a 13 year-old car from the 'points and carb' era, in that condition, had been able to do the same.
Chris