Looking for advice and/or resources

I was looking for a towing rig last Autumn and came across this old forest service 1991 R2500 Suburban and had to have it. It's turned out not only to be great for towing, but it gets all kinds of attention. It drives great and has been more fun to own than just about anything I've had, and I've had some really great cars.

I think it's amazing as it is, but I have some stuff in mind to improve it and wondering about others' experiences and advice.

Here's the list of thing I'm interested in doing:

1. Dash replacement - who has the best product for the money?
2. Replacing gauge bezel - new or used?
3. Rear disc brake conversion - worth it?
4. 20" or 22" smoothies - best brand, price?
5. Static or bagged lowering without affecting towing capacity?
6. Rust protection without coating the underside with gunk.

Thanks!