Revised Standard Version and Good News Bible insert a paragraph break here, which is appropriate.

So the king chose Bacchides, one of the king’s friends, governor of the province Beyond the River: The connector So is not necessary (so Good News Bible). A better way to begin this verse is “Demetrius did as they requested and chose….” For the king’s friends, see the comments on 1Macc 2.18. The River is the Euphrates. Beyond the River is a name that was used during the days of the Persian Empire for one of its provinces. It refers to the territory west of the Euphrates River all the way to the border of Egypt. In fact, it is the territory that Antiochus~IV entrusted to Lysias (see 1Macc 3.32). Good News Bible calls it “Greater Syria.” The simplest approach might be to render the province Beyond the River as “the western part of the kingdom” or more specifically, “the region of his kingdom between Egypt and the Euphrates River.”

He was a great man in the kingdom and was faithful to the king: Good News Bible has a good model here, and so does Contemporary English Version with “Bacchides was a powerful and loyal official.”

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on 1-2 Maccabees. (UBS Helps for Translators). New York: UBS, 2011. For this and other handbooks for translators see here.