I think you put a lot of thought and effort into your design, and I do think it looks cool. But I agree there are some problems that you might want to think about before you invest time effort and money into the build.
I have to agree about the weight issue: my sis had done one of the triangle shaped tractors years ago and it did not have as much wood as does yours. She could not move it: it took her, her husband and a vehicle to move the beast!
I cant even imagine adding the weight of soil and water in addition.
If you really want those herbs up there, though, (for insulating?) then I suggest getting/making light weight planters that can be removed and carried to the new position.
It seems that most people who start experimenting with tractor design are doing so for weight, mobility, and unlevel terrain issues. Many people seem to end up adding a tarp for shade on at least a portion of the run, too.
From having tried a thin wheeled wheelbarrow (chinese cart) I can say that you will have two problems with using bicycle wheels: first they will dig into the ground from the weight, making it hard to push. Second, they can bend and wobble, especially when you are trying to turn, and this is made worse by them digging into the ground. This is why atvs, tractors, wheelbarrows, beach bikes all have fat tires.
While the shutters are a cool find, i dont think I would consider them predator proof. They tend to have some flexibility between slats, thus a racoon could easily get a paw in. Some are also made of wood that is quite weak and could be broken by a determined predator. I hope you check that before using them.
I really dont intend this to be demeaning of your idea in any way. I have just personally concluded that for a small set up one would be best off having a permanent coop with small run, and just having a wire frame day pen that can moved around the yard. I have yet to see a chicken tractor design that incorporates the coop that overcomes all the problems.