i want to make sure that they are both safe?
Use common sense and dont park too far away from the public eye.
tomtoms with europe maps included.
Got me to Polish border no problem, after that I know the route.
safe speed to drive on the motor way in mph
70 - 90 mph, again use your sense.
any guess at how much it would cost in a car that size
Used 2.0litre toyota, it cost between 180 -200 pounds depending on how fast you like driving.
how many time i might need to stop, the less stops for me the better,
If youre the sole driver, get a good nights sleep prior to leaving, hopefully a morning start. Aim to get as far as Berlin, then stop and kip for an hour. Any longer and you tend to feel more tired than before you stopped. ( people are different and you may need extra stops, this is only my recommendation based on me personally ). After this you are approx. 2hrs from the Polish border. Central Polish cities ie. Gdansk, Warsaw, Krakow, a further 5hrs.
If you are able to share - drive, the journey should be quicker.DONT FORGET CLUNK - CLICK..... HAVE A SAFE TRIP.