2001 Ranger idles rough, CEL, low power, remotely located

Father in-law recently bought a used 2001 Ranger XLT for our homestead. 113K miles.

It never accelerated well. It took a while to get it up to 80MPH on the freeway, and after only a couple of miles the check-engine light began flashing and it struggled to maintain ~60MPH. Once I finally got off the highway, I noticed the engine idling very rough, and the breather hose between the valve-cover and air intake had popped-loose from the air intake. I reconnected it; no change. It limped the 15 miles home on side-roads, the CEL alternating periodically between solid and flashing.

I'm over an hour away from a mechanic, so am trying to assess my options. I ordered new spark-plugs and a wrench to see what the old ones look like, and a new MAF sensor. Air-filter is clean enough. The popped-off breather may indicate something "expensive" happened. I'm reluctant to drive it for an hour, as something worse may occur.

What would you do in my position?