Welcome Paul,
I understand your concern on the plastic interiors. Be sure to peruse member Sneakinup's photo gallery on what he did with his '72 Overlander. With paint, and his own skillfulness, he addressed both what-to-do-with-the-plastic, and roll-up (tambour) doors.
The additional hole in the sink can be repaired - there are many threads on similar damage.
Good luck,
Tom