You shouldn't put the load on the front, above the front wheel(s). That's the worst possible location for multiple reasons.
- It'll get you smacked on the road:
200kg located above the front wheel sure will be heavy enough to pull you over for a nice face-plant on the road upon braking. The inertia will 'pull you over' when you brake. The higher you place it, the worse it gets. You get a bonus at that when leaning in on a corner, worsening it even further.
- Steering will be heavy:
The rotational inertia means a large mass can be hard to rotate. In other words. It'll be much heavier to turn your steerer with a heavy load attached to it.
- The front tyre(s) already gets the most abuse upon breaking, putting a load on it worsens that.
- Steering behaviour such as turning-radius, or minimum speed required to make a turn may get worse.
I'd make a three-wheeler with two wheels at the rear, and a load space between them, just in front of the rear axle, close to the ground. This will give you the a good result because:
- Your steering can remain as simple and lightweight as that of a normal bike. You won't have to take into account Ackermann. The steering like on old horse carriages would also eliminate the need for that, but it would create an awful ride experience.
- Mass is located close to ground, keeping its negative effect upon steering and 'leaning in' to a minimum.
- Mass is located at the rear, preventing it from causing unexpected effects upon braking and steering, which are hard to counter yourself.
- You can easily create more space there for cargo than on a rack on your steerer.
- You can access the cargo easily with eg. a handtruck. You'll save your back/spine and energy.
In short, I recommend to design it like this, preferable i'd be locating the mass closer to the ground though:
Rather than this: