Once you gain traction and get some deals the good news is you can hire a VA to at least to the initial calls for you (less no's) and you only talk to the ones interested in your offer (I know it because I run a call center for Real Estate).Mailers can also work, in that case interested sellers reach out to you, mailers can be expensive though so its also a numbers game.

-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.

Then the real work begins, following up with them until you can book an appointment or at least get on a zoom call to talk further.A VA caller can help (I run a Real Estate call center) but the second part you need to do on your own, the VA caller can help shake the tree and find hand raisers.

What would you suggest is the best course of treatment?

Just a quick note @Caroline Gerardo that raw land can qualify for 1031 treatment. 

Does anybody use an outbound call center for making cold/warm calls? 

Also don't forget to look into your tax treatment for signage.

These communities often feature amenities such as fitness centers, swimming pools, and communal spaces, providing residents with a high-quality living experience without the burdens of homeownership maintenance.Moreover, the low housing supply in Sunbelt states has created an opportune environment for BTR developers and investors.

However if I get something totally cold from some call center I'm immediately hanging up and blocking the number. 

I also think many of the call center people they employ are not even in the US.