Phew. All done and ready for the Maker Faire. And it runs and runs great! In the end, I learned:
1) My choice for track works well in one direction only. Going in reverse throws a track
2) 2.5HP is not enough
3) I over engineered it in the effort to make it 'Heavy Duty'. I should have stuck to a metal body
4) I would use straight through axles for the road wheels. I have 16 pillow block bearings there. Each weights close to 3lbs. I could do fine with axles and 8 bearings instead.
5) The lexan sprung bogie is not strong enough for heavy duty work. I have to switch to metal
6) Electric is not the way to go for something this heavy. The motors are way too heavy and the 8 batteries are killer in terms of weight.
But...I love it!