Sen Monorom is a city in Mondulkiri.
It takes 7-8 hours from Phnom Penh but a new paved road is in the process of being built so the trip will probably be shorter when it is finished. It cost around 8-10 dollars from Phnom Penh
The easiest way to get around is on moto.
There is not much to see in the city. There is a small market next to the bus station.
You can join a tour to see the minorities (Phnongs) in the small surrounding villages including the regions many waterfalls. You can also go trekking in the surrounding forest; but sadly there is not much left. Do not expect to see any animals as poaching and logging is widespread. WWF has some project in the areas and they might pay of in the future so more animals will be sighted in the region. WWF are planning to open a project in Srepok River but for now there are not enough animals but maybe late in 2010 or 2011 they will open. You can spend a day at "the elephant valley project" watching sick elephants. You can not ride them and will basically just look at them a whole day while the mahouts will walk around with them. It cost 50 dollars and can be mediated by the old American man at "The Middle of Somewhere" next to the Greenhouse and not far from the round about. But you should maybe ask yourself if your 50 dollars could be spent in a better way. The project is a bit strange and it is not much different from watching the elephants in a zoo. Here you just have to do it a whole day! Many of the guesthouses also arrange elephant trekking and home stays at the minority groups. It is possible to rent mountain bikes, motos and dirt bikes in the city (ask at the Greenhouse). The guide attached to “The Middle of Somewhere”, an old Khmer rouge soldier will not bring women into the forest – so if you are female, do not waist your time - ask somewhere else.
You can buy scarves and other handicrafts made by the minority people in the shops around the city as well as coffee and honey.
There is a good Khmer restaurant close to "The Middle of Somewhere" and by the river Bananas owned by a Dutch lady is also very good. The Greenhouse is a must for backpackers. It has a good vibe and a very friendly owner. He can arrange for tours and speaks good English. He is also employed by WWF and knows what goes on in the region.