Goat carts are pretty easy. One of the things I wanted to do with my land was build a small machine shop for building Prototypes of horse drawn vehicles.
Goats are strong for pulling but I wouldnt want too much weight on their backs pushing down or under their tummies pulling up. Balance for a two wheeled vehicle is essential.
A four wheeled vehicle and Game is ON. or even a three wheeled vehicle. Using a caster wheel in the front and two fixed wheels in the back.
now we just need 2 years to produce and grow out a wether goat!!