There's a pretty little truck in our shop from the 1970's right now. It's called the 1971 Dodge Adventurer. She's being worked on as we speak so lets give you some details if your unsure what they were made for.
in 1971 The Adventurer was introduced as the "Lifestyle" pick-up truck. They were designed so families could take vacations and haul campers and trailers. They were made comfortable but made tough and did not give up any durability.
The new thing for Dodge W-100s in the 1970's was automatic transmissions and for manual people they introduced the three speed transmission. A new "easy off" tailgate was installed so they could be removed easily without any tools. Handy for those people who go camping a lot.
If you would like to read more check out the article I found here: http://www.allpar.com/model/ram/ram-trucks-D.html