My vote is different (-which is often the case here, SO I apologize in advance!!
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I have a Powermatic 143 that I have modified with upgrades such as better tires, a 1¾hp motor, roller blade guides, etc. where it does quick breakdown work of your stock materials. We use it constantly ...and we use it with a 3TPI blade 90% of the time, -and a 14TPI blade the other 10%. I have a scroll saw that was 'inherited' by me from a family member so I can't get rid of it, but there is no real use for it IMHO. A Scroll Saw is only really used in clock making, luthier work, and similar crafting. It is much too slow and generally does not have a deep enough throat.
FWIW, technology has advanced in wood working since time is extremely valuable these days where many older tools have become obsolete. At minimum, you really need a Planer, a Mitre Saw, a Band Saw, a Router Table, and an orbital hand palm sander. If you have a table saw, you can use it for spinning a stacked Dado which will be helpful, and for breaking down your stock.
As far as other pieces, I would suggest you spend some time on your local Craigslist and Marketplace and buy the following used tools. My reasoning is that you can have them during the fabrication process, and then resell them to regain your investment when you are finished. I have a Jet JSG96 Belt & Disc sander that will be perfect for making your templates for a flush trim router, and for angle shaping or shaping radius' quickly. I feel you really need to find something similar. I mentioned a Router Lift Table above, and the same things applies with this tool. If you take your existing worn/deteriorated wood, you can add body filler to the worn or deteriorated areas and then sand it smooth, -or if it is not fitting correctly (shrinkage, notched incorrectly, etc.) you can add wood filler or cheap body filler and use the belt & disc sander to make your template the correct size. So, rough cut your new wood stock using the Band Saw with the 3TPI blade to quickly cut it to rough-size, then use two-sided tape to attach the old and new pieces together. Then using a 0.250" or a 0.500" diameter Flush Trim Router Bit to trim the new piece of wood to actual size. Items such as Roof Ribs, Roof Rails, and even some structural wood can all be cut & shaped in this method.
While Radial Arm Saws are kind of a thing of the past, on certain units you can add a stacked Dado head to make Tenons, Lap joints or Bridle joints, -or maybe some Rabbet joints. If not, use your Router to cut the Rabbets, or your Table Saw. Depending on where you purchase your wood, I feel you are going to need a Jointer and a Planer. Both of mine are WAY too large to be used in a small home shop, but a small Planer at minimum to create two good surfaces in case you need to do glue-ups to make bigger pieces such as front seat upper wood, or upper Rear Rail wood or Rear Belt corner wood will be a plus. The bottom line in this is you will stay much more enthused if it takes 40 hour to manufacture all of the pieces vs. 100 hours using a scroll saw, a jig saw, and a handheld belt sander. I wish you were closer since many of the tools you need I have already purchased and have fixtures/jigs setup, which would be a time saver for you.
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