While reading through this posting I wanted to share that reconstructing maintenance records for a Part 91 aircraft shouldn't be so difficult so as to be insurmountable. Pull FAA Advisory Circular 43-9C, with Change 2 - its available for free on the FAA website. Para 12 tells you how to re-establish lost records, excerpt below:
12. LOST OR DESTROYED RECORDS. Occasionally, the records for an aircraft are lost or destroyed. In order to reconstruct them, it is necessary to establish the total time in service of the airframe. This can be done by reference to other records that reflect the time in service; research of records maintained by repair facilities; and reference to records maintained by individual mechanics, etc. When these things have been done and the record is still incomplete, the owner/operator may make a notarized statement in the new record describing the loss and establishing the time in service based on the research and the best estimate of time in service.
You'll need to have an A&P or IA go through and verify all AD's, do an Annual, validate any STC's you can find such as the Horton STOL you mentioned, validate obvious repairs in accordance with the Cessna Service/Part Manuals and so on. The engine is "on condition" - TBO is only a recommended number for non-commercial aircraft, same for the propeller. And again, so on...
Take your time and document as it looks like you are doing all of the rework and maintenance, rebuild yourself a flyer, do it right and you'll go a long way to restoring its value. In my opinion, value is what someone else will pay for it so if your plan is to get the best value for the rebuilt project - worry about the rebuild quality first, and the 'lost records' second or third. The FAA rules allow you to make a "best estimate". Do just that.
PS: Those early 182's fly great, keep it a nose dragger.