Matt --
You'll find a lot of information on girls by searching the board for locations, recommendations, etc. Use "The Device"...it can be your best friend. Cost-wise, figure 50 euro.
As for directions, the site below has a nice map of the coffeshops... for Greenhouse Centrum, essentially you'll head up Damrak to Dam Square and turn left, but it's definitely closer than you think.
http://www.coffeeshop.freeuk.com/
Nope, I'm not in the city, but weather-wise, you should plan for showers, sun and wind.
And yes, familiarity will help speed up the process.
Enjoy! And don't forget to contribute to this site, as its value is imeasurable!!