I recently had a client that went through this - the local permitting office required that a GC come out and inspect the property and perform any required work, and then they would inspect the addition. 

. - A full gut of the home was performed.- A bathroom was added.- Exterior siding and all new windows. - Total private money in the deal $104,000.- The whole project took only took 4 weeks to complete.- The home went pending twice with the same agent causing delays and additional hold costs. 

How does a renovated property will perform in this depressed rental market?

Not sure how you can resolve the issue of over/under salting to accurately forecast cost, but you may want to consider having them use a calcium-magnesium-acetate snow melt in lieu of traditional rock salt.

Is this accurate?

Which company was the provider, how long have you had the property, and how has it performed? 

But you can invest in a 506(b) along with other IRA investors that may lack the knowledge to perform adequate due diligence.To me, this is starting to look like black market investing for your retirement. 

If you don't have access to a broker just yet then Reonomy is the next best thing. it does cost around $500/mo least i checked and you can only download 500 leads per month but the data is rich and accurate and you can get super granular on what asset type you're looking for.

Second, handling general contractors and holding them to cost, schedule, and performance.

Make sure you are accurate with your determinations after all you are the one providing the numbers.You are doing all things correctly from what it sounds like.