The only trailer you have that might concern me would be the horse trailer. In the picture it doesn't appear to overload the truck but what does it look like with horses in it? Yeah, brakes would be my only concern. If possible I would see if I could hook up electric brakes. I really like the system U-Hall uses in brakes. It uses the vehicles deceleration to initiate the trailer brakes; no need for electric brakes.
BTW, my favorite of your trailers is the one with the little blue car on it.
