On Friday, December 7, 2012 12:56:55 PM UTC-6, Tony Palermo wrote:
But I would still need to stain, seal, and varnish the door!

Leon may be on to something. If your doorway area can accommodate remodeling/adding to, to fend off the weather, and cost is not a problem, then remodeling would certainly help.

Why stain? The wood is naturally dark, already. More darkness, of the doorway, is not going to do much good, if any, for its protection against the elements. What is your concern, here, looks or protection against the elements? If your topcoat finish doesn't hold up against the weather, the stain under it is going to accomplish what?

A thinned marine finish (whichever one you choose) would be your initial sealant (apply two coats if there is doubt) and the subsequent non-thinned finish would be your (varnish) top coating. The thinned application and the non-thinned application are compatible, so you wouldn't have to worry about sealant-finish compatibility.

Sonny