Decided to go ahead with the top end engine fix.
The engine rebuilder says in his experience the rebuilt heads and new timing components should last at least another 5 years. Looks like I will be sticking around the forum after all. I could buy another high mileage used KK for the same amount it costs to do the heads and timing components on this one, but another Jeep will come with unknown problems. Mine is 4" lifted with skid plates, recovery points, rock sliders, roof rack, and more. I know my Jeep will need a steering rack, rear shocks, rear main seal, and eventually the transmission. I have all those parts sitting in my basement. The front suspension has been fully rebuilt. The rear suspension has new control arms. It has a new radiator, transmission cooler, and fuel pump. All the maintenance has been done on schedule or sooner. Engine is a Jasper refurbished (bottom end now). Underbody rust is cosmetic not structural. It looks like a 217,000 mile Jeep but that is ok with me.
Johnny, if I had the garage space to install an engine myself I might have gone that route of a refurbished engine. But with the labor to install (here in the east coast megalopolis), it would have come to $5-6000. I'm still spending 2/3 of that, but I know it will run like a watch when they get done with it. Another 5 years will put it at about 300,000 miles.