Welcome to Khao San Road-- where outdoor bars advertise "very strong cocktails... we no check IDs," and tattoo parlors boast: "new needle everytime." The list of rules in the guest house I checked into on Soi Rumbuttri (parallel to Khao San and much calmer) gave me a clue as to what kinds of things I could expect: somewhere between "do not leave valuables in your room" and "check out is at noon" was the warning "do not bring prostitutes into the guest house."
Khao San road is the backpacker hub of Bangkok-- an area that lives in a perpetual state of college spring break. Coming from Northern Thailand in the low tourist season, it's sort of a shock to see so many foreigners in one place. The only locals here are the ones trying to make a buck (selling pad thai, hair braiding services, buckets of vodka, etc.) or bring home a Western boyfriend (I thought that was a stereotype, but there's truth to the idea that Western boyfriends are highly prized here). Also, you may be able to see some "ladyboys"-- Thai men who appear as beautiful women, some even going to such extremes as to have ribs removed.
I would not recommend staying on Khao San Road or booking any tours from here. In researching the best ways to get to Siem Reap, I was told that some big scams are run from Khao San. An unsuspecting tourist may book a minibus to Cambodia and then encounter a staged border crossing and surprise visa fees. And, although this sad little tourist was told they would arrive at 7pm, they'll roll up past 11pm in front of a guest house... one that has tipped the drivers to stop there late.
Legit overground travel to Cambodia from Bangkok still has its troubles. You can get an air-conditioned bus to a town near the Cambodian border, but then you have to get a tuk-tuk to the place where you can buy a visa. If you don't have US dollars, they'll give you a terrible conversion rate. You also need an extra passport photo. Once you have your visa, you have to find a bus that will take you in to Siem Reap, but air-conditioned busses don't exist, and the roads are terrible. And they're kept that way on purpose. Bangkok Airways, which has a monopoly on the flight from Bangkok to Siem Reap, pays the Cambodian government not to fix the roads, encouraging tourists to fly. All travel guides will tell you it's an absolute rip-off but definitely the way to go if you can afford it. So, wary of all that could go wrong overland, that's what I did.
When I arrived at the Siem Reap airport, I bought a visa and a scan of my passport photo for 22 dollars. Already having governmental corruption on my mind, I was really uneasy when two of the officers joked among themselves and took pictures of me with their cell phones (wtf!?). Once I paid, my passport was handed down a long line of uniformed guys (really-- like fifteen of them, no joke), and I had to wait for them to call my name. I was the last one called, so I was by myself (I'm not sure if I'm paranoid, but I think they did this on purpose). Finally they called my name and then put up a CLOSED sign in my face. They said it was break time and I needed to come back in an hour. I laughed it off, and joked with them, "nooo come on guys, I just saw you with my passport..." but inside I was kind of freaking out. These creepy guys have my passport and I'm alone in Cambodia! But it turned out fine-- they were ribbing me, studying my passport and asking me about Texas. One guy said he had some relatives that run a donut shop in Dallas.
Anyway, I'm here in Siem Reap at an awesome hostel, and I'm about to go watch the sunset at Angkor Wat.