I've been doing some research on smaller trucks to replace the F-250 I
have now. The main criteria is something that Mrs.E will feel
comfortable driving (meaning smaller) yet still has the tow capacity to
handle the little camper she bought last summer. Ideal would be a tow
capacity of 5K to 6K lbs to tow the little 4K lb. camper.

I happened to be looking at the Tacoma and recalled you posting that
yours is rated to tow 6,400 lbs. You also have said you have the four
cylinder, 4x4 with a manual transmission.

You might want to verify your tow rating for that configuration.
According to Toyota, it is only rated to tow 3,500 lbs. (2016 model
specs).