From the back cover:
The journey there is half the battle.
The road to adventure is never an easy one. Whether travelling on horseback through lonely forest wildernesses, with a caravan across rolling planes, or by stalwart ship, danger awaits in the shape of escaped slaves, imprisoned mermaids, swarming elementals, blink bunnies, insane inventors, peeved trolls, possessed livestock, and a bevy of other hazards to block your way.
From the publisher's site:
By Land or by Sea, like the original En Route, is a collection of short encounters that GMs can easily insert into longer adventures of their own design, or use as transitions between published modules. En Route II features scenarios suitable to sea voyages as well as to land-bound travel, which can be played in about one hour's time. It promises to be just as useful and popular as the original!