Fantastic car Kyle. I love Grandes. $3,800 is an insanely good deal for that car. Your car looks to be in excellent shape and is very nicely optioned. In terms of the AC compressor, be sure to get a modern Sanden compressor and I would switch to R134a refrigerant at the same time. You can get the sanden/R134a conversion kit from
Classic Auto Air which also has all the parts for original factory air systems.
The houndstooth upholstery in your car is actually quite rare and until very recently upholstery kits with the houndstooth option were not available. I really like it. I know West Coast Cougar sells them (as this was also an option on deluxe interior cougars in 1970). If your seat upholstery is all good except for the tears in the houndstooth on the drivers seat, don't replace the whole thing. You can buy the houdstooth material and have that sewn in to your original seats. The original upholstery is so nice you want to replace as little as is necessary.
I'm not completely sure if the vinyl top trim is reproduced (It will be in NPD's online catalog if it is available). Most repro chrome trim is quite poor quality so you really want to hunt down some good used or NOS stuff. If you keep an eye on eBay it does come up every once in a while. There were actually multiple vinyl roof options on the grande starting with a base 'half' vinyl roof or landau roof. I actually think the full roof like your looks better but most Grandes seem to have the half roof version.
Here's an example of the trim you're looking for
http://cgi.ebay.com/ebaymotors/1970-Mustang-Coupe-Grande-VINYL-TOP-BELT-TRIM-RH-SIDE_W0QQitemZ370281515392QQcmdZViewItemQQptZMotor s_Car_Truck_Parts_Accessories?hash=item56367f8980
Here's a complete set but also including the front ones for the half roof version which you don't need.
http://cgi.ebay.com/ebaymotors/1970-Mustang-Grande-Coupe-half-vinyl-top-trim-molding_W0QQitemZ390115134926QQcmdZViewItemQQptZMo tors_Car_Truck_Parts_Accessories?hash=item5ad4ac8d ce
