Transportation from Don Muang Airport to Khao San Road and from Khao San Road [on hold]

Transportation from Don Muang Airport to Khao San Road and from Khao San
Road [on hold]

I'm coming from Singapore and I will arrive in Bangkok via the Don Muang
Airport. So I need to know a few things. I will be travelling alone and
it's my first time doing so. I do not know Thai as well.
1) What's the price of a taxi from Don Muang Airport to Khaosan Road? I'll
be staying in Dang Derm Hotel
2) How much is a cab from Khaosan to the silom nightlife areas?bars and etc?
3) I would like to go from Khao san to Pattaya. Most probably Citin Garden
Resort. Any ideas how i can get there without taking a cab? A straight
(bus air conditioned) from somewhere nearby would be ok. Last option would
be a cab. How much would that be as well?
4) From the Citin Garden Resort to Don Muang airport. I would also need to
know what transportation to take. Any ideas how i can get back to don
muang airport? Prices as well would be a great help.