I can give you my assessment on it if you would like.  

The assessed "value" of this home, is $550,000, although there is absolutely no chance that this home could even come close to that if listed in today's market.A release of mortgage was issued by the bank in 2005 for the value of $440,000.  

One home may not be comparable to another and vice versa.From personal experience, I find park managers/owners and mobile home dealerships to be a good source of information when assessing values. 

Back taxes are paid and they've lowered the assessment. 

All agencies use the Underwriters to produce the Title Commitment all the work and risk assessment is done by the Underwriter.

In a given month, iFunding evaluates several hundred deals each month and only lists a small percentage of those, based in part on our assessment of comps.

Does the property cash flow after PITI, condo fees, management fee, cap ex, vacancy, special assessments? 

Just an update, two roofers came and gave their assessment.

The tax assessment probably has no relationship to the value.To a buy and hold investor the house value is determined by the rent they can receive. 

There must be other ways for you to reach the property owner and negotiate what you need to be able to properly make an assessment prior to making an offer.