I’d say they moved from hill to hill with a nearby waterhole and plants in the surround.
“hill to hill” is probably the correct answer. But, still, they had to head in a generally consistent direction (south) and not go in circles over the years. It’s fascinating looking at the early human migrations out of Africa, through the middle east, across the inhospitable steppes and mountains of the Asian continent, up to the bitter cold of the north (which makes no sense), then across the Bering land bridge and eventually south again. Most migrations would logically be toward more abundant hunting and foraging. Going north to the frozen wastes doesn’t make sense.