CudagGal, thanks for sharing the picture. Just at a glance it is in decent shape! Like Challenger RTA said, start with a good car wash. You can check the fluids yourself. Transmission should be in good shape. It's the toughest transmission ever and even if it leaked a little, it would still work. The engine is the biggest concern because if it wasn't turned over periodically, damage to the valve train, again like Challenger RTA said.
Start another post in the "Restoration" section and start posting photos of what the brake fluid, coolant, motor oil and transmission fluid looks like. We can tell a lot from that! Also, go slow and ask lots of questions. We're here to help.
Your father was a very smart man putting you before his car! The Hemicuda can be brought back. And leaving the car to you must have special meaning to him and you!
If you can, block out the last few digits of the VIN and VON on the fender tag and post a picture. I circled them in the attached photo of my 70 Challenger Fender Tag (they're in the lower right hand corner of the tag). This will help us determine the value.