The other thing you need to look for is rust under the dash. You'll buy it on a dry day and then when it rains, your floor pans will fill up wth water!!
There are air vents on the front window sill outside (where the wipers are). Dirt and leaves gather in here over the years and block the drain holes up under the dash which causes rust. Just get a water hose and run it in the vents and all over the windscreen for a minute and see if any comes out under the dash (inside). The drain holes are just behind the front panels, infront of the front door hinges.
Be carefull not to spray water down the genuine air vents inside that sill vent, then you will get water inside for sure. There are raised shields around the genuine air vent intakes whick allow the water to run off OK.
Sorry for the ramble! Let us know how you go!