I replaced all the factory speakers in our MKX about a year ago. The front doors had these...6x8s that are fed full signal from the head unit with a crossover built on that sends highs to the tweeters.
The tweeters have a raised center section:
So you could almost simply drill a hole in the large black plastic area on the door panels on the Ranger (above and forward of the door handles), recess that raised area into the hole, and epoxy the mounting holes to the back side, and it just may work great, and free! I'll have to pull the door panel and plug it in first to see what it sounds like. Speaker says 4-ohm on it so I'm sure it would be fine.
I'm sure it wouldn't make for show quality sound but it would be a free improvement.