> 1. I will have US dollars. Should I change them for Euro at the airport before I take the train to the city?

You will need euros. You can exchange at the airport or use ATM to withdraw in euros. I recommend having at least 20 euros or so on you before you get to the city. There many exchange bureaus in the city but you may be tempted by waffles or fries along the way :-)

> 2. I have read on one of the links that the coffee shops are for drugs?!? How can one know if a place is good just for a cup of coffee and a cigarette (tobacco!)?

Very true. Coffeshops are for marijuana. If that is what you want, they are actually very pleasant and friendly and likely to be full of American, British, and Australian tourists. The coffeeshops are like restaurants - you'll be seated at table, given a menu probably told the specials of the day and a server will wait on you.

If you want coffee, avoid coffeeshops and look for cafes. There are many obvious places such as Starbucks-like establishments, pastry shops, or eetcafes. And the coffee is good...

> 3. Is everything more or less in walking distance or should I get one of the day passes with museum entrance discount?

I recommend a day pass and a day tram pass. Many things are in walking distance but it is so convenient to hop on a tram. They come frequently and are located all over the city. I believe the day passes (there is a one day tourist bundle) also has voucher or ticket for a canal boat tour.

Erina Washington, DC