Caravan/Voyager :: 1996 Van Started Chugging - Random Misfire / Bad Cylinder

Last week, my van started chugging and the keydance code indicated random misfire. I changed the front spark plugs and wires and it ran a little better but still showed the error. Took it to my trusted mechanic and he changed the back 3 wires and plugs and the coil pack. Code now showed misfire on one of the back cylinders(I forgot which one). 2 Mechanics both confirmed good spark and gas at the cylinder. He is saying that there is a mechanical problem in the cylinder and the fix would be over $1k.

The van has over 250k on it so it's not worth the engine work. I asked about a compression test and was told that it's almost impossible to test the rear cylinders without doing a ton of work, and that they are 95% sure that it is a mechanical problem with the cylinder. I've known the mechanic for over 20 years and he is an honest guy, and knows that I won't do the expensive repair, so he's not trying to rip me off.

I don't have the facilities or knowledge to do the work, so it looks like I'm screwed. Is there anything else that I should be doing before I write the van off? It does run, but very rough at low speed, and no power at high speed, and mech says that the unburned gas will eventually screw things up.