Tax Delinquent house that's been vacant for 5 years.

[Benjamin Harris]

Hey guys this is my first post on here.  I'm a beginning real estate investor located in Virginia, and am looking at a house that's come up on a local county tax delinquent property sale.   I've determined that the house has been unoccupied for 5 years, but I also was able to get into it and look around.  It is still fully furnished, with lots of cobwebs, dead insects and some water showing in the basement.  I've researched what to look for in properties that have been vacant for a while and got some good ideas there, and now am trying to determine what my top dollar should be when I go to the auction.  At the very least it will need major cleaning, and some mold remediation.  Maybe some new kitchen appliances and possibly some plumbing as well.  The buy who owned apparently got sick one day and went to the doctor for a checkup, and never came back (died).   So it still looks like he just left for the afternoon.  But in the year or so leading up to his death, there had been a number of improvements including vinyl siding, vinyl windows, water heater, finished basement, and maybe a little before that a heat pump.  The house looks good on the outside (and the neighbor has been mowing the .25 acre lot) and it's in a decent neighborhood. 

How would you go about determining a max bid?  Realtor.com and Trulia show estimates around $95-$100k, which of course would be a habitable house, which this is not currently.  County tax assessment is $73k.  Similar size houses within a few blocks are listing for $95k-$115k.  I know it will need a roof in the not to distant future, and who knows what else you'll find when you turn on the water and electric.  Any ideas?