Paksan is in Bolikhamsai Provinc, in central Laos. It is not a particular appealing town but has become a busy place (by Lao standards) due to the ever increasing traffic on Highway 13.
There are regular buses in both directions of Highway 13, i.e. to Vientiane and Pakse (US$10, 10h to 15h depending on the bus) and everywhere in between. Buses going to Vietnam by the Cau Treo border also pass here. The most popular boarding place is in front of the market (on the other side of the bridge than the Paksan Hotel). Just flag anything down you like.
For buses to more local destinations, there's a bus terminal next to the market.
There are a number of waterfalls to be seen in the Phou Khao Kuai National park. One is Tad Xay another Tad Leuk.
Noodle soup and sometimes also a bit more variety in dishes can be found at and opposite the market and also on the east side of the bridge.
There are a few guesthouses around town, particularly at the eastern and western ends of the town along Highway 13. The following options are within a reasonable distance of the market and the main bus terminal.