You know what? I hate that adventure games (FPS adventures too) seem to think that people run or walk everywhere. There is a deadline, and you are trying to beat it. There is a real sense of urgency; walking the whole way seems silly to me.
Once you get used to it, those portions are enjoyable. The Buggy was a lot of fun. I only wish I could have ridden ant-lions too.
Imagine having mode of transport that leaps 40-60 yards at a time.