Last night after recharging the battery, I fired the old girl up and took her for a limited drive up and down the lanes to my barn and out to the road. No insurance so I can't get out on the road but I have probably 300' of twisting driveway out to the road and another 150' of twists over to the barn.

The good news:
Despite sitting for quite a while in an unheated barn in cold Ohio weather, the car nearly started after the first glow. It stumbled a bit and tried but failed. It started on the second glow, which I take as a good sign on a diesel, my compression should be decent.
After the front end work (knuckle, UCA, sway bar bushings) on the damaged side, the steering and handling seem just fine.
I was able to get up to enough speed to get the car to shift from first to second so it 'seems' my transmission is working properly.

The news that tells me I have more work to do mechanically (other than the fan apparently slightly contacting the plastic shroud, thought I had that fixed already):

Despite changing the air filter, cleaning the air filter housing, cleaning the vacuum line from the valve cover to the air filter housing, changing both fuel filters, getting the plastic pipe to the turbo properly sealed via boots and clamps, and cleaning the ALDA banjo bolt (wasn't that bad at all), the car still has a definite misfire and poor acceleration. It was dark by the time I got home from work but based on the video my son took of the car as it went by him on the driveway, I could see a decent amount of sooty exhaust in the glow from the taillights at a throttle position that probably shouldn't create that much exhaust based on other diesels I've owned.

I know the car drove back from California last summer and was running and driving when it was hit. I can't imagine someone would drive it with this kind of misfire so I have to lean towards something from the impact causing the misfire. Would a problem in the vacuum system cause a misfire?

I know already I have a vacuum leak because the engine will only shut off with the lever on the injection pump and I thought the leak would be in the lock circuit to the driver's door in the hinge area where the car was hit. Oddly enough, the power window on the front door still works and I would think that power cable runs the same place as the vacuum line. Regardless, I'm going to pull the panel under the dash on the driver's side and whatever else is needed to get to that vacuum line and cap it off prior to where it leaves the body for the door. Once the car shuts off with the key, I guess I'll know the vacuum system is working properly and I can see if the misfire gets better.

I did break off the vacuum line at the ALDA because of the cold but I replaced a large section of it with polyurethane vacuum line I bought for a B5 Passat some years ago, so that should be good.

I did see a thin coating of black sludge on the underside of the main fuel filter housing and the prefilter was black and opaque so I question when the filter was last changed. I do have a can of diesel purge that came with another vehicle I bought some years ago. I was thinking of filling the main filter with that as many times as possible and seeing if it would clean the injectors if a vacuum leak wasn't behind the misfire.

Any thoughts or suggestions? I need to get rid of the misfire before I move on to the body, which will be a major expense.

PS. I was able to get the glovebox door open and found the all of the original owners manuals etc in there with lots of stamps for ongoing maintenance in the booklet. Also found the original owner's name and index cards in his handwriting indicating exact mileage for the various maintenance/services that were done. It appears that this car is what the PO told me....a well cared for one elderly owner California car. Kind of neat to have proof of that, though.