I know Im being way too critical the first 4 minutes into it, but I find it hard to believe Robin Williams' character has such young cildren. I understand some men start families later in life, but here's what I would have done:
Make the kids older... NOT like the vacation movies older.
Again, just into it but thought I needed to start analyzing it. lol
Just Do It
This movie is a comedy. By your attitude, I can tell that you are not going to like it.
Not everything in the movie makes perfect sense. This movie ignored some of the facts to keep the comedy going.
I like the movie, but you are being too critical. Just watch it knowing that it is a cheesy movie. Don't take it too seriously and I think you will find it funny. I think it is funny.
Plus, maybe Robin Williams is supposed to be playing a younger guy. Give him a break. He was good for the part.