I am not a fan of red interiors.
If the exterior is red I would not paint the interior metel pieces, just leave them red, that will look ok, red goes well with black.
As far as painting the vinal pieces like door panels, that looks ok if the panels are in good shape. Otherwise just buy new, they are pretty inexpensive.
Its cheaper to find a j-yard black seat than it is to have your red one redone.
Get a JC Whitney truck catalog.