I believe the track segments are 60", and you can connect two to have a full length set up, if desired. Bar width is camper dependent, as Charlie mentioned.
The Yakima track sections are 5', 60" as mentioned above. On my Grandby the bar length is 78". there is a fair amount of the bar outside each foot, but doesn't extend beyond the width of camper.
This is exactly the info I was looking for. Thanks everyone. Amazon sells the whole rack package but as I expected, its probably smaller than I need it to be. I will probably start with one 60" length and then decide if I need to go the full length. Thanks again!