To get a better idea of value, here's the information set you need to provide (in addition to pictures, as mentioned above):
VIN (from dash) and door data plate info - these VIN's should match if the door is supposed to be original.
Condition report on what you know that can't be seen in the pictures
Any known history on the car
List of options
List of known modifications, if any
Trouble spots that pictures should include are the trunk floor, floor pans, trunk drop-offs, frame rails, fender lips, quarter panel lips, inner fender aprons and shock towers, inner trunk and hood lips. These are all common rust areas for these cars.
That will at least get us into a reasonable ballpark estimate that you should then use only as a guide while doing an in-person inspection. Although I have bought cars sight-unseen over the Internet, I have always had someone in the area from a forum covering that vehicle check it out for me before buying.