Hey JJ,
Obviously alot depends on the market of where the property is located. I can't touch on how much you would be able to sell it for because I don't know that market. To answer your questions though I would say:
1. No. Just by removing a tenant that would not increase your value by 17k. I am not sure if I understood fully regarding that question but if you're asking that at face value the answer to me is no.
2. In regards to what you should rehab, that will depend on its ARV (After Repair Value). I would contact your insurance to see if you are able to get a new roof on it thru insurance. New roofs are great for resale value. You can also look at making cosmetic upgrades (siding, interior cosmetic) If the property value can be increased to, for example, 150k by putting in 20-30k work that seems to me like it would be worth it. Also, by improving the property you should be increasing your potential rental rates. Again, this would depend on the area surrounding it. I.E. - is the rental growth and value add limited by surrounding area?
To sum it up, it all depends on what the market is in that area and what the ARV would be for the property.