My current campaign takes place in The New Lands far from the homelands of the PC's. Anyone traveling to The New Lands faces health threats from enduring the rigors of the crossing.
Rigors of the Crossing:
All occupants of a vessel that make a crossing of the Allatian Sea must make 1d4 saves per crossing or face a malady with each failed save.
Maladies for Men and Related Races
1 -1 STR, Rickets
2 -1 CON, Grippe
3 -1 DEX, The Shakes
4 -1 CHA, Gull-pox
5 -1 INT, Magnus' Palsy
6 -1 WIS, St. Germaine's Malaise
Each month on land without particular treatment allows a save to remove one ailment acquired during the crossing. Bed rest for a month provides a +4 bonus to that save. A months' bed rest is an expensive luxury in remote colonial settlements.
Beasts making the crossing may suffer even more than men do having to make 2-5 saves or suffer as follows on each failed save.
Maladies for Horses and other Beasts
1 lose 1d8 h.p. , Whimpering Whinnies
2 move reduced by 10', Pawrot
3 -2 to saves vs physical elements, Belly Ripples
4 -2 to save vs magic, Druid's Bane
5 -2 to morale, Whitemane
6 -2 to attack rolls, Smokey Eye's
If a beasts malady is not specifically cured within 3 months it is permanent.
This chart serves 2 purposes it serves as a gross abstraction for how draining long sea voyages can be and it discourages frequent trips back and forth across the sea from colonies to homeland.