1965 Dodge Dart 270 Wagon

Nice! I too have a 270 wagon but will be pulling all the side trim off. I've acquired both a roof rack and power tailgate window for future installation. I found any kind of replacement seat covers would be expensive unless one went with generic replacements. To solve the problem I will be fitting a 65/66 Barracuda interior (rear fold down seat and front buckets) as upholstery for that is readily available (it's already been test fit and fits perfectly!). As you surmised the tailgate will be a problem unless you can find someone parting a wagon out with a good tailgate - I've bought 2 decent ones as my original is rotted out. I'll be happy to provide any info I can as my resto is both stock and custom-orientated.
Sounds like your build will be interesting. Do you have a thread started that I can track?

I'm torn on which way to go with mine. Personally I would lean toward going more custom with a custom modernized dash and interior, maybe a floor shifter or a swap to the older pushbutton just for fun. With it being a family heirloom situation I feel obligated to restore it more traditionally. I'd love to find a way to get something AWD stuffed into it for the icy Colorado winters, but I don't have the requisite skills to pull it off myself and I'm sure the budget to have somebody else do it would be quite large. I haven't seen anything done previously that I could use as a guide.

I will have to look into the barracuda seating. I really like the idea of keeping the front bench, but even having funds available for the project I cringe at spending $500/seat. You mentioned that you are pulling all of your side trim. Is it in good condition? Are you interested in selling it only as a whole set or would you be willing to part it out? As you can see in my second picture the front driver side fender has been beat up a bit. I have the trim piece that is broken off, but if you're willing to part with the pieces for that fender I would gladly take it off your hands instead of trying to repair mine.