Have you considered a double draw single tongue yoke for your horses.
I calculate the sholder weight on each horse to be less than 150 pounds, based on an 8 foot single bar extension to a 17' Casita with a hitch weight of less than 500 pounds.
I am certain the two Percherons can pull the 3,000 pound tow weight without to much difficulty.
now see thats why i come here
my current wagon is an old airforce bomb wagon[poetic aint it from bombs to picnic and parade duty]
i can hitch tandem, 1 in front of the other single, [my favorite] or double hitch.
or pull 1 bolt and slide in a 2 in ball coupler
shoulder weight will be very low as i will have wheels in front google up pioneer forecart.
my daughter and i both love the casita
[meg especially] but they may have a problem i cant over come that large beautiful bathroom in front. i plan on being able to drive from inside the trailer at least part time.
the last thing i want is to be sick or hurt in 33 degree rain in front of a trailer tire.although my horse would prob just stop and look at me if i did fall
off.he has done this many times under saddle.
and once pulled a skid stop on pavement to keep from running over 3 kids who looked both ways before stepping in front of a wagon and freight weighing
in at at least 5000 lbs GOOD PUPPY BAD HUMAN!!!!!
good ideas all keep em coming guys