I agree that capacity is not an issue. Both ball-and-socket and recreational pin-and-plate systems are available with several times the capacity needed for a Scamp 19'.
Even if you do have multiple trailers, a ball hitch works fine, as long as (unlike Scamp) you use the common ball size (2-5/16") at a reasonably common height (not far above a typical full-size pickup box floor). I think a typical farm has more than one trailer.
Regardless of the number of trailers interchanged, a fifth-wheel hitch does have the advantage - as Jared mentioned - of back-in coupling. I've never towed with one, but it seems easier, and big rig drivers certainly do it quickly and easily.
Unfortunately, even the lightest available fifth-wheel hitch is much heavier and bulkier than a ball and coupler. Just to confuse the choice further, there are couplers for balls that also couple by backing in like a fifth-wheel; the Quick-Bite
that Jared mentioned is the one I've seen for conventional trailers (which could be fit to a Scamp 19'), and I recently noticed a much heavier unit
for more typical "gooseneck" trailer structures.