Granted, our market has skyrocketed in the last year, but to be off by 25-30% leaves me wondering if I want to ever visit their site again.

If the owner has been trying to fix a problem on the property (sewer, units allowed, etc) there's more often that not a person in the local admin/planning dept that knows all about the history of the parcel, and an in-person visit is usually worth your time.

Not much of an update so far ... the roof is almost done however we had rain and thunderstorms here that caused a slight delay.Last week had someone visiting from CA that came to the property, so that was neat. 

Simple Google searches or visiting sites like the Bogleheads forum can yield pretty solid advice pretty quickly.Learning to budget well is one of the big items a planner could help with.  

Once you file a permit, does it automatically trigger NYC Finance to come visit and assess your home for property taxes?

Each of the properties I purchased by auction were advertised as being Occupied but by the time I closed and visited the property, the occupants had left.  

Even if I am only back for a short visit, I'd definitely like to attend a meeting.

Visit lots of open homes (starting now) to see where your competition is.

Since they've left I've visited the property and done a few rounds of back and forth to figure out a renovation layout that would be physically possible, and to get bids from my contractors.

I'd suggest you actually visit the neighborhood, not rely on Google maps.