If you have concerns about your property tax assessment, try contacting them to ask for an informal review first - this is free!

@Eric Bilderback I Don't know any 'rules of thumb' for this situation, but I would be most concerned about when the electrical and plumbing were redone, check the foundation, hvac systems and roof.  

It would be a permanent residence as well an occupation.

One last concern I had was the contractor told me they glued the rubber roof straight to they plywood instead of laying down felt. 

I'm concerned about cold calling brokers and somehow turning them off when they hear I'm an investor.

@Karen A. you are right to be concerned about outside and underground issues.

My concern is that since I am starting out, finding a good contractor could be difficult and costly.

The question/idea you have is far to vague and what little detail you provide are acts that would be very concerning.  

If the 45 days concerns you then sell your old property contingent upon finding a suitable replacement prior to close.  

Many times the forms you will find on the internet are not very good and/or don't address specific local concerns and requirements.