I’d get the Tacoma. It’s a better truck. I also agree with you - I don’t like side-facing seats. They’re dangerous if you get into a crash. The human body does a lot better with sudden deceleration front/back than it does side/side, especially since there isn’t a good way to belt in to a sidemount seat that guarantees you won’t slip out of the belt unless you get a 5 point harness.
That said, either one will last a long time assuming you take care of it. As for parts, I can give you anecdotal evidence that Toyota is better at supplying parts for older cars. I still have no trouble getting new factory parts for my 93 MR2, and the guys in my car club with 80’s era MR2s are also still able to get most parts. That combined with the fact that the Tacoma isn’t going anywhere any time soon means that you’ll probably be able to get parts for it longer.
Have you looked at the Nissan Frontier King Cab? It starts at $18,200 while the Tacoma starts at $19,700. I did not check the standard features, but you might prefer the Frontier anyway, given the price. My cousin has a Frontier Crew Cab and she likes it a lot.
Both are good trucks and don’t worry about parts, or a lack thereof. Parts for the Ranger will be available for an eternity due to the large market for them.
You can’t get parts for a '98 Saturn? That doesn’t sound right. Where are you shopping?
I always thought of Rangers as junky. Here in Mexico, they take older Rangers, which are allowed in once they are over 10 years old by customs. They keep them running almost indefinitely. There are mechanics who specialize in those old vehicles, and car parts stores in small rural towns which have things like tail light lenses, etc. Yes, they need a lot of repairs, but compared to what a new vehicle costs, you can do a lot of work on an old Ranger when labor is cheap.