I viewed a house today with some serious sub-flooring issues.The house is built up off the ground and the plinths underneath are clearly collapsing.The tile floor inside is still in good condition but the floors slope up and down.Can anyone give an idea about methods and cost for fixing this?

You can compare a local market's current condition to its past performance and try to deduce what it may do over the next year or two. 

They are both lead generators and designed to convert prospects (or pre-condition to convert more easily).

When a tenant fills out an application, one of the questions is "Would you participate in AUTOPAY if it were a condition of acceptance?"  

Once the tenant calls the board of health or even just complains to you about any unsafe conditions, it is illegal to evict them in Massachusetts. 

Plus, the VA has some pretty strict requirements on the condition of the property.. 

Where most of my units are (Escondido, CA) it is hot but the tenants do not expect air conditioning. 

There's no good way to answer that question without knowing so much more information than can reasonably be discussed here - market conditions, zoning, permitting, labor costs, location, etc.

with that being said, i've had the sellers agent not willing  to tell me what the condition of a vacant property is!

You could always try to get the seller to give you some sort of verbal 'guestimate'of what it would take to get the property into a livable/rentable condition -- they should have some sort of idea.With the repair 'guestimate' and ARV of the property, you should be able to make an offer that is contingent on the actual repair numbers being at or below what the seller estimated.