Is there any way that I can keep the deck without demolishing it since to rebuild a new one is pretty expensive?

I would say the quickest way for you to get past that fear is to think about the worst case scenario, and realize it isn't that bad.If you lost Everything in real estate...you still have a career, BAH, BAS, SGLI, GI-bill, etc...so you will be able to rebuild and go for it again.Don't overleverage, or take on more risk than you're comfortable with, but understand that the reward greatly outweighs the risk.

So far we feel our only two options are to walk away from everything and let our credit take the hit (rebuild it in the future) or throw more money into both properties and pay half and half on the personal loan (6 year term) and the credit cards or sell the quad and bring another 9k to the closing and keep the duplex for as long as we can and hope that the tenants pay their rent and that we don't have to make any serious repairs (already purchased a new furnace and had to pay for plumbing issues as well). 

You cannot trust any numbers that sellers give you -- you have to rebuild the income and expenses for the park from the ground up. 

Start rebuilding your credit today.

My insurance provider has stated they will not do this, they issue policies for replacement cost to rebuild in case of a total loss and have provided their replacement estimates which match to the amount of insurance coverage in the policy.I am kind of at a loss as to what to do or provide further.

The tearing out is much easier than the rebuilding process. 

.$20,000 lien on the property that the lien holder has agreed to settle for $3,000After repair value of $135,000Repair Estimate of $25,000Houses could rent for 2,200 or more.I am working on rebuilding my credit.

From your last post it sounds like there will be a supply glut with so many wanting to sell so it will be an interesting development to follow as the rebuilding continues.

There's a particular building that has the zoning for this use already established but would need a complete rebuild.