Thanks for all of the replies. I decided to book my side trip to Siem Riep for 4 days.

Looks like everyone loves the Golden Banana Resort, if there are any other recommendations, feel free to leave them.

Thanks again

As an aside, I will be flying out of Siem Riep to BKK arriving 4:40pm. I have a seperate flight booked out of BKK at 7:10 pm that evening for SFO. This enough time (I hope) to switch? (Since it won't be through one reservation, I'm worried about all of the checking in and out again.)