Here's an overview of this 1-4 player game that plays in 60-90 minutes:
The aim of Wayfarers of the South Tigris is to be the player with the most victory points (VP) at the game's end. Points are primarily gained by mapping the land, water, and sky. Players can also gain points from upgrading their caravans, by gaining inspiration from nobles, and by influencing the three guilds of science, politics, and trade. As they make discoveries, players want to quickly journal their progress. The game ends once one player has journaled enough to gain membership in one of the three guilds.
You can find a short summary of all three titles — each of which will contain a solo mode — and teasers for the next two titles in Garphill's "Ancient Anthology Series" (the first two being Raiders of Scythia and Hadrian's Wall, and the third being a solo-only campaign game set in China) here thanks to BGG user Technik.
For more details, you can watch the presentation yourself, which begins at the 4:30 mark: