Here's what I found. If you can get your hands one these, they have a lot of great info.
Challenge Magazine Issue #25 (1986)
Featured articles on campaign structure and adventure design for Traveller referees.
Included tools for balancing encounters and developing subplots.
Challenge Magazine Issue #34 (1988)
Provided practical referee advice, including campaign planning tips and how to handle Jump travel and logistics.
Also offered short adventures and NPCs that could be slotted into a larger campaign.
Challenge Magazine Issue #39 (1989)
Contained the article "Campaigns: From One to Many", which discussed scaling up from solo adventures to more complex campaign arcs.
Challenge Magazine Issue #44 (1990)
Focused on Traveller: The New Era and had deep material on political intrigue and long-term campaign threads.
Included referee tips for sandbox vs. plotted play.