Complex sentence: One of the key motivations was the desire to travel as cheaply as possible, mainly to extend the length of time away from home, and so journeys were carried out by "thumbing" (hitchhiking), or cheap, private buses that travelled the route.
Split into simpler sentences: One of the key elements was traveling as cheaply as possible, mainly to extend the length of time away from home. As such, journeys were carried out by "thumbing" (hitchhiking), or cheap, private buses that travelled the route.