It appears the property is in bad shape, what can you tell me about the condition and is the tenant causing more and more damage?

Along the way discovered some of the walls were rotted out due to previous termite damage.

You said it isn't obvious that it's coming from the roof, but if rainwater is coming in from one damaged area it can easily be pooling and then traveling to that area of the house.

Make sure you get a "Release Fee" on each property; this is an amount that is to be paid to release a property as collateral in the event you need to sell, or if you have an insurance loss that insurance proceeds will be applied to the subject property and not to the whole loan keeping you stuck with an encumbered damaged property, remember they don't make construction loans as a second and the blanket loan won't subordinate (usually) to another lender, it could get messy, so have a release fee stated and understand how payments will be applied.A line of credit is not a blanket mortgage but a line of credit can use other collateral, different animal and it may or may not fit you needs.

Hold your tenants financially responsible for the damages. 

First thing that needs to be done is hire a professional roofing contractor and get it done right , to avoid more damage .Deal with Chuck in what ever way you see fit . 

Previous condition: water damage, substantial rehab.Rehab cost:90k- Oakland Single family, comp: 600k ; listing fo 325k.

Every turnover I do is littered with scuffed up, dirty, and damaged trim and doors, especially if they are white.

Investors with experience know how to dress a property well for a newbie investor and they try to unload a problem to you. 

Prior to selling, the buyer's inspection turned up significant mold damage to the property's foundation due to water leakage.