Break-in instructions are on page 8-16 of the owner's manual
http://content.gmownercenter.yahoo.c...aro_owners.pdf - they don't indicate anything about long trips though mention not driving at any constant speed speed fast or slow. You should vary your highway speed to avoid just running at the limit.
From my experience the challenge was keeping it under 4000rpms when merging onto the highway - I recall needing to accelerate hard and clearly going over 4000rpms once but not worried about it.