A Traveller in Space: Age of Colonization

If you are looking for a low tech simple scifi setting for use with your traveller game might I suggest an age of colonization: O'Neil cylinder colonies travelling between our solar system and the centauri system on a seventy  six thousand year transit. To get there they create a series of artificial stars with a thousand year life span...created by sunmaker ships ahead of the colonies so they can reach a sheltering fire once every year to heat up the colonies and recharge batteries. This means fast moving transports ships can move up and down the trail. Out there in interstellar space million ton colonies are pushing onward to an uncertain destiny. Some are unable to cope with that...maybe some colonies vanish from the trail, some are destroyed, some hit by raider factions who have a new plan, while crazed 'reavers' looking to kill folks and wear their skins begin increased attacks.
And maybe an artefact of alien origin...so the sunmaker changes course...leading colonists to a terrifying discovery.