I just pulled up a CoreLogic automatic valuation for this property and it arrives at a current estimated value of: $650,877 with 61% confidence
Estimated value range: $416,561 - $885,193
CoreLogic will give a ballpark idea of value and of course your Realtor can help you determine what offer you should make based on the upgrades, site, etc.
This doesn't appear to be in a designated flood zone so that is also a good thing. You would want to verify that as well since flood rates have increased substantially.
All the best,
Alma Rose Kee, PA
Sold On Tampa Team
Future Home Realty