My boyfriend & I traveled to Cambodia the past week and contemplated a lot on obtaining an e-visa / visa on arrival - we decided to go ahead with visa on arrival.
We entered cambodia via a government bus - Transport Co.Ltd from Mo-chit northern bus terminal (BKK) starting 8:00 am and reached us at Poipet bus stand around noon. The visa process is fairly simple while entering cambodia as to exiting the country.
Entering the country:
* Exit Thailand visa at the Visa Embassy in Thailand
* Enter Cambodia embassay - Visa fee is 30$ per person (yes, the officials do scam , they showed us a piece of paper which asked for 200 baht as their processing fee but we refused to pay & they don't really impose)
* We hadn't taken a direct bus and could only avail bus services from Mo-chit to Poipet in Bkk - there is a free bus shuttle from cambodian border to the next bus stand that takes you to Siem reap - Bus to Reap is about 3.5-4 hours and 9$ per person.
* As you get off at the stand - you have tuk tuk drivers assisting you to pub street/old market etc.
(Smiley guesthouse at Siem reap , slightly off pub street is a good place to stay at - we paid 10$ a night for a private room)
On your way out of Cambodia
* We brought our tickets to BKK (Direct bus cum taxi in thailand) for 9$
* Tuk tuk came to pick us up from the guesthouse to the bus stop . We boarded the bus at 9:00 am and where at Cambodia - Poipet in 3 hours.
There is the tricky part
* If you have a double entry visa , the cambodian officials will sign you off on the departure immigration card but if you haven't got your 2nd single entry visa from India - you are required to visit the thailand embassy , pay the 1000 bath visa fee and fill a visa form and get back to the cambodian officials right at the border (this is least a 15 min walking distance per way)
* As you hold a Indian passport , you can stand on the last counter that reads "VISA ON ARRIVAL" and cut through the huge line which has various nationalities looking to get their visa's done.
* Once you reach back with the thailand visa form filled , you head back to the border - they sign you out and re-visit the thailand embassy , hand over your passport & stand in the "VISA ON ARRIVAL" line for collection of your passport & other formalities.
We had a tuk tuk waiting for us in thailand that escorted us to a restaurant where we could eat some lunch and then head to Khaosan in BKK by 9:00 PM.
As the visa process differentiates for different nationalities and extremely time consuming the journey then proves to be more than estimated time. We traveled for 12 hours only to party again at Khaosan.
Hope this is helpful :)