Budget Travel - New York City to Phnom Penh

I am currently living/ working in New York City. I have a friend who's working in Phnom Penh for the next 18 months or so, and I'm thinking about paying him a visit. I'm not particular about when I go, I just want to fly as cheaply as possible. Because I'm a 22-year-old girl who's going to be travelling by myself, I have worries about taking local busses or trains.
I would hopefully like to fly out of an airport around my area (willing to travel to DC, NJ, Boston, or any other city in the area) and fly into PP.
If you have bus/train suggestions in Asia, please tell me how safe this is, what I need to know/ have prepared, and whether or not you would reccomend it to a 22 yr old girl travelling by herself to Cambodia for the first time.
Please let me know what you all think would be the cheapest option for me! Also, when is the best season to go? (Cheap, not too hot, not too crowded, etc.)

Thanks xx

I suspect that the basic plan would involve getting to Bangkok or Singapore from some US destination (and this would likely involve a change of planes in either Europe or Asia) and then take a flight from there to Phnom Penh.

It has been a while since I was there, but buying a ticket to Phnom Penh once you are in SE Asia would likely be cheaper than trying to ticket the whole journey in one transaction.

I imagine that the cheapest time to visit would be during the monsoon season (summer, if I'm not mistaken). November through February is the high season, as I recall.

i think the most direct routing for flights is taking an Eva Air flight to Taipei then connecting to PP

I am west coast based, so my experience is based on travel from there. I also fly Star Alliance, so am not familiar with Korean Air, Eva Air, etc. There are probably good possibilities through Taiwan and/or Seoul, but I wouldn't know.

Look for a non-peak season (peak season = best weather) ticket to Bangkok. Fly midweek. Then fly Air Asia to Phnom Penh. Expect to spend close to $1K.

Sometimes there are cheap airfares to Saigon and you can take a bus to PP from there. Vietnam to Cambodia is safe enough, the tourist trail is well traveled.

Express tourist buses in Southeast Asia are fairly nice and comfortable. Local buses less so, although very cheap. The bus from Bangkok to PP is a grueling 2 day trip through Battambang. If you go that route, spend the night in B'bang.

Trains are not happening right now in Cambodia. You can take a train to the border from Bangkok, but the bus is a better deal.