Need help repairing exterior door

Hey all,
My (century-old) house has a detached garage. The door by which I (and not my vehicle) enters and leaves the garage needs help, and I don't know what I'm doing, so I figured I'd ask you all to share your experiences.
The bottom end of the hinge stile has rotted out (the rot stops below the bottom hinge, so structurally, I think the door is OK), and the bottom rail fell off last week. So I can tell that the door was cope-and-stick, and the bottom rail was held in by 4 1/2" dowels in each end. I need to repair or replace before the winter gets here. South-west ohio, so I'm looking forward to about a foor of snow falling (and then melting) over the next four months. Oh, and the door is going to be painted white.
All of the interior doors in the house have a five-panel design, two long parallel vertical panels at the top, a horizontal panel across the door at the height of the door knob, and two shorter vertical panels below that. On the door to the garage, the two upper panels are replaced by a single window. So the door has four rails, one at the bottom, one below the middle panel, one between the middle panel and the window, and one at the top. The door measures a shade under 84" tall, 32" wide, and 1 3/8th inch thick. At the blue BORG, I found a similar door in the catablog that they would be willing to special-order, for around $400. No money left for that kind of outlay right now.
The damaged area of the stile is on the inside edge (toward panel and rails, opposite hinges), and up from the bottom. The damage goes no higher than the bottom nine inches. But the glue joint between the middle two rails and the hinge stile have failed. The glue joint to the top rail looks intact.
In a fit of enthusiasm, I bought a Bondo Rotted Wood Repair Kit that looks like it has enough material to replace the wood that is totally missing. I also have stockes of Titebond III and slow-set epoxy.
I've taken a wire brush to the damaged area, and some came off. Along the joint to the rail, on the inside side of the door, about half the thickness of the stile is gone And what is left is pretty spongy. Again, it's the bottom 9 inches. The stile is 5 1/4" wide (and just under 84" long). The damage is about 4" wide, 9" tall, and the whole thickness of the piece. Inside edge, where it joins the bottom rail.
I could leave all the spongy bits, and use 6 coats of the wood stabilizer that came in the bondo kit, as per the instructions. Then fill in the rotted area with the filler, and set the filler around new dowels I insert into the rail. I wonder about how strong the bondo will be? That joint will be in compression, as the weight of the door is pivoting into the hinge stile.
My second choice is to be more agressive with cutting out the soft bits. Then the Bondo filler is the whole thickness of the door, 1 3/8 inches.
My third choice is to totally cut off the bottom of the stile, and to mill a solid replacement piece. How would I join the new piece to the old piece? Biscuits? Dowels? Scarf? I have a scrap of pressure treated wood big enough. Will pressure treated wood glue normally? I'm leery of milling it down in my basement workshop, as I have a vacuum cleaner sucking through a separator lid on a garbage can for dust collection, and no air filter. The router table could come up the stairs and outside, though. I've never tried to mill such a complicated profile with the router; I'd need (elliptical? must measure precisely) cove and round-over bits. I have a straight bit, and my ogee might work to complete the profile.
Anyway, thanks for any input. I'll check in over the next few days, and summarize any responses sent in email.
Chris
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snipped-for-privacy@gmail.com wrote:
<snip>

I'd go with a fourth choice and replace the door and jamb with a steel unit.
--
Jack Novak
Buffalo, NY - USA
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Considering that you can buy a new pre-hung steel door and jamb unit for about $100, I agree option 4 is your best bet. It should not take you more than 4-5 hours to have a brand new insulated door in place.
Colbyt
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