Hi bonnie,
Just a few thoughts based on the comments/suggestions
for your consideration:
1- Bolt the hinges through the door for the extra strength It'll give.
Use a fender washer on the back to spread the forces and a lock
washer a/o nut. You can probably find/make something to cover
that up on the inside that would match/blend in with your door facing [cedar is it?].
or just do that to the plywood and put a corresponding hole on the
underneath of the cladding to mate up with and thus cover the washer and nut.
2- I'd use exterior paint. Maybe you could find some color mix rejects at the
paint store/counter. They're supposed to be quite cheap if available.
3- Using the aluminum flashing in one or a couple strips/thicknesses around
the door may be the easiest way without adding too much extra diameter length/dimension.
It is easy to cut with an utility knife believe it or not - no need to
use metal shears. Determine the circumference and the depth/width/
door thickness needed [@2&1/2in if used with two 1/4in skins and 2in
foam?]. Mark with a fine point sharpie that measurement along the
determined circumference length needed and connect the measurement
points with a single thin line to delineate the @2&1/2in strip width
needed. Alternately, if you have an adjustable square, you can set it
to the @2&1/2in width length and use the thin sharpie point in the
end detent and mark the width of the circumference strip length by
running the sliding/adjustable edge along the factory edge. Using a
metal framing square edge, or something similar, [an 18in x 24in
framing square works well] held just on the thin sharpie line you've drawn
on the flashing, score the flashing with a new sharp blade in a utility
knife, holding it perpendicular to the flashing surface and against the
metal square edge [as a guide] using moderate pressure about 3-4 times,
and proceed along the total length until done. The piece should easily
and cleanly snap off. I always wear leather work gloves and score it nice
and steadily, not forcing it. It is not too time consuming or very difficult
to do. Then glue that to the outside edge/end of the plywood and foam sandwich.
[It just occurred to me; that you may want to have the width of the circumference
strip be just shy of the total door thickness - say 1/16th or 1/8thin less - to
avoid having it wider than the door thickness and thus interfering with the cladding.]
I Googled glues and found this:
http://www.liquidnails.com/products/pro ... oductId=78 .
It says it works with metal, foam and wood. I have no experience with
it but it'd be a start perhaps. Maybe you could do a small experimental
piece and make a small cross section like the edge of the door from scraps
and see if you can glue a small piece of aluminum flashing like you would be doing
on the door. The one thing I would do, though, would be to try and ensure the glue
is spread evenly on the surface/surfaces - [however it says to apply it
- on one or both surfaces as it instructs], maybe by using a notched trowel
[I have seen small plastic notched applicators by the glues/mastics in some
stores] or even a plastic knife perhaps.
Not trying to make your life with this too difficult or complicated! Ha! Just thought the
above may be a method that would work. The glue may also possibly be able to
attach the circumference weather strip seal for you too. One tube shouldn't be too expensive
to get to do a little experimenting with I'd hope.
'Continued good luck, you're doing great so far.
Cheers,
Norm/mezmo
If you have a house - you have a hobby.
Norm, I think you've already answered my question about what to cover with. Still wondering if bondo would work. Too bad I'don't have any of the Foam Factory's stuff; bet it would work, too.
and dangerous. 
Wood graining can become Addictive!!! I’ve mentioned that before ... 
- appreciate the boost PcH !
Did end up cleaning the garage and getting things a bit more organized. I hope to work a bit tomorrow. The heat's not helping, either.