Re: Is it possible nowadays to travel by car..
First, it cant be a family trip if you mean with children. It would be insane to travel from Nepal to London with kids tagging along. Dont do it.
No matter how much you plan, and how far in advance you plan - you'll have troubles at borders. The more countries you cross, the more times you need a carnet de passage, the more times you'll be exploited by border guards aswell. Remember, these border are seldom used, and the border guards are poor and lonely. Bribes are common, so are delays at the borders.
From afghanistan to turkey, no matter if you travel through the balkans or if you go through arabia - you'll be scared for your life. Any history lesson will tell you why that particular leg wont be enjoyable.
In cities, things are not different. You're a south asian with an expendible income, visiting some of the most isolated and poor places in the world - you'll stick out like a sore thumb. Prices will be inflated, you'll be stalked, and the local police gangs will hound you to know why you're there. The locals at times wont be the most accomodating bunch. Some will, but for most of your trek they wont.
Think very hard about this. The trip itself will be rewarding, but the situations that come up - and they will - will be scary. There is nothing romantic about it. Adventerous? Yes, but not romantic. If you want romantic, stick to Dubai-London.
Skip nepal - iran for another trip.
Make sure you research repair shops, have lots of money set aside, and enough resources to rough it out for a month.
There are plenty of books, for the time being, read one. I'd suggest Adventure Capitalist by Jim Rogers