I know I need a reliable contractor that can not only do the work, but help me in assessing properties before offers are put in so I am open to more contractor options. 

People do lose assets to unexpected high tax assessments so it is something to be aware of.

Hey, I just thought I would check in and see if you made any progress on your assessment of MHPs in the past 7 months?

Ultimately I’m trying to assess in the current market how competitive this offer is.

Hey @Jim Rusco, also take some time and find out of there are any special assessments on the horizon.

Not to be argumentative, but @Huong Luu's assessment is not really accurate.

My question is, how do I assess how much approximately the cost for the rehab will be?

My first place was 50k that is now worth $110,000 and I rent it for $1100 a month so I got a steal with that one...until that special assessment comes...but it has produced a 150% ROI over 4 years so far.

I agree with above - definitely get a contractor(s) to come with you when you get permission to assess the property from the inside. 

Often times, the real estate tax bill can increase substantially in year 2 if you don't double check the current assessed value versus the purchase price.