Interior Disassembly, part 1 - seats, carpets, and first look at the floors.
The interior is the first part of the teardown. It needs to come out for two reasons. First, we need to get a good look at the floors (a notorious Mustang trouble spot - they tend to be rusted out and/or badly patched). Looking under the car, the floors look good on this car, but you really won't know until the carpet comes out. The second reason is this car is a musty, moldy, smelly mess - everything soft has absorbed the odors of - what? Mice? - and will have to be replaced/rebuilt. So the seats, the carpets, the dash, headliner, all of it has to come out. Then the interior trim panels will be removed, and the floors can be evaluated.