My dad use to have a 1981 ford F250 for his farm truck. Had the 302 in it. HUGE engine bay. Could climb up into it, put your feet on the engine mount, while you sat on top of the fender, and that was easy. I remember changing a Fuel filter with my dad once on there, and from start to finish, the filter was plain as day in our sights with out taking anything apart.
I've always liked working on the straight six engines on jeeps. From the old 4.2 carbed engine that I believe originated when AMC owned jeep. Either AMC or Kaiser. That's the engine my dad had in his jeep wrangler from the say he bought it brand new in 86 as one of the first ever wranglers off the lines for the 87 model year. He put 300k+ miles on that engine and NEVER even had to rebuild it once. I dont think he ever even had to remove the head ever. But then again, it wasn't a weak aluminum block/head. Cast iron. Then in 91, they started putting the much more familiar 4.0 straight six in the wranglers, which is what every wrangler I had, had. Just about the same as the 4.2, still cast iron, but now fuel injected with a lot more power. But those 4.0s where easy as hell to work on. All 6 spark plugs right in plain view. But on 98, jeep switched the 4.0 from cast iron to a much weaker aluminum.
Now, I haven't had to work on my STS yet, but it looks like with the V6 there's plenty of room to work on it, once I remove all the plastic trimming.