So, CAD work has progressed, I now have the design of the whole bot and have a chassis printed off ready for assembly.
It prints off in a single piece with no supports, taking nearly 8 hours!
It took me a while to settle on the design, as I had to cram in all the components (2x Arduino Pro Mini, 2x Adafruit DRV8833, battery and receiver). After AWS60 I'll look into finding a better microcontroller solution. The plan is to have a hinged 0.5mm titanium plough on the front, hopefully there is enough weight.
I've also printed off the parts for the wheels and started assembling them.
I will probably have to redo the wheels, as I've noticed that as the wheel rotates, the side parts holding the rollers in place will contact the ground. I may also have to add grip to the rollers. I might do this by using O rings like I normally do, or find some grippy tape. I'll also have to remove the back shafts on these motors.
Lastly, I have finally decided on a name for the bot. Because I've spent a long time trying to think of a name, it will be called Error 404 - Robot Name Not Found.