My plan is to paint the interior of mine first, then the exterior. I think that's the way they were done at the factory (as if that makes any difference

) as I found some exterior overspray on the seat frame skirt. Either way it will need to be masked, but I don't plan on doing an extensive masking job for interior paint (after all, I'll need to get inside it.

)
That link you posted is a good idea, but my firewall is going to be the same color as the exterior (factory did that.) So I'm not going to put it on it's nose.
My cab is sitting on a pallet with casters, but it really needs to be a bit higher so I can get the lower parts of the cab without laying on the ground. I'm too old to do a lot of that. Getting back up gets harder every day.
