I managed to evict the tenant after several more months, a court date, and a significant amount of property damage. 

My question is how can I assess the damage the leak has caused?

-Has no crawlspace (common for older properties) so we couldn't see the foundation-Drywood termite/wood decaying fungi damage seen on all the windows/doors/parts of the beam on the exterior, parts of roof decking and rafters in the attic-Old leaks/moisture damage seen in the ceilings and attic-Parts of the roof has patch work-Roof doesn't have any permits on record (don't know how old it is)Seller's offer to me:-Fumigation treatment for drywood termites (tenting the house)-Replace and repair all damage wood throughout the house-Replace the entire roof with a new permit-Replace one window in every room (not all)-Pay for a structural engineer to inspect the foundation-Offer to get quotes for repairs and have a 15-20K budget to make all repairs, house is 500K.

Where I live in Lake Tahoe, Nevada there are HOA associations have been poorly run, multiple insurance claims from snow damage, and as a result are increasing fees to cover the low fees of the past and capital expenditures that have been put off for years. 

The court will probably find that there was no opportunity for the lender to become aware of the transfer, thus violating their rights under the contract, and will award damages to the lender.

I deal with a roofing company they do a lot of storm damage ( insurance claim ) work . 

Your house build won't kill you physically, but it certainly will most probably damage you financially in a big way.On the schedule and budget point - yes, I'm saying that builders with 20 years experience and an entire team of experienced subcontractors are not able to complete a home on time or on budget due to COVID and general supply chain issues.   

Love to hear your thoughts- AC unit needs to have an exterior side panels and brackets to support to secure the unit- Do not screw into the window sash as this will damage the window and you will be responsible- Install weather striping to avoid water or critters from entering your unit- Unit needs to be tipped towards the outside to avoid condensation and damage to floors- Landlord is not responsible for their Air conditioning unit if broken- Tenant is responsible for window, floor, ceiling damages caused by poorly installed window unit- Window unit should not be installed before May 1st and must be removed by Oct 1st

She is requesting the carpet stretching not be done until her tenancy ends, which normally I'd be fine with, but I've been told waiting too long to address it could damage the carpet long term (this is a higher end rental).

Once a foreclosure is commenced the borrower's credit is severely damaged.