I'd just do maintenance as the shop manual suggests. That's what I do on my '49, I grease it every 1000 miles, etc.
I've found that the spray on undercoating works quite well. I buy the rubberized asphalt type. I've only ever used the spray bomb type. IT can be removed with kerosene if you need to stick a wrench on the nuts and bolts. I find that the wheel wells need to be re-undercoated nearly every year. But, it's pretty wet here, and I drive all year.
