Figured the 8500-8750 range was a good deal.
What's the lifespan on the SOHC, and average total miles before its dumb timing chain needs to be replaced?
The timing chain itself is rarely, if ever, the issue. The hydraulic chain tensioners are the problem. They have a spring to hold tension when pressurized oil is not available (like during cranking) that wears out. That plus if the maintenance was poor the tensioner can not hold good pressure against the chain, which allows it to slap against the guide, eventually breaking it. The tensioners themselves are not expensive, nor difficult to replace.
I picked up an 04 Explorer earlier this year, 200K on it, and it had a slight rattle above 2000 RPM. I slapped some new tensioners in it and BAM, rattle gone. The tensioners themselves only cost me about $70, but that's employee pricing. Time to install is minimal, and no special tools are needed, just a 27mm socket and a 27mm wrench.
On the Explorer they are out in the open, on a Ranger the front one may need the intake, or at least the throttle body, removed, but the Explorer intake is very different.
While those issues were mostly worked out by 05, I would still consider the tensioners to be a long-term maintenance item. I'm getting ready to do my dad's when it gets warm again, and he'll have about 175K by then.