I need to give up my dog!!!!!?

I got him for my dad about a year ago. He was a pup then. A german shep mix. He is about 80 lbs and an outside dog. My dad passed almost 3 months and I cannot take him in. He has never car ridden before. What can I do, I have no time to train and dog is 50 miles away....going weekly and it is taking a huge toll on me. Dog is healthy, I need HELP, HELP HELP. I don't want to put him down He only knows me so adopting is not good. all rescues are full and won't accept a larger dog. He wont ride, scared... please help me. If u had an 18 month old child would you open the door and let the toddler out to fin for him/herself? That is what I am facing.....PLEASE HELP ME. Having an effect on my health....I am grieving and have this to work with also. No one wants him due to his large size and economy. HELP HELP HELP