>Was Ruger an independent brigade or within the 1st division?

Brigadier General Thomas H. Ruger commanded the Third Brigade of the 1st division of the 12th Army Corps. He was the senior officer of the division after Brigadier General Williams.

When Brigadier General Henry H. Lockwood reported to Gettysburg, he brought an unattached brigade which was assigned to the 1st division of the 12th Corps. Lockwood, an able officer, was unfamiliar to Williams or Slocum. He was also senior to Ruger.

When Williams took over command of the 12th Corps, he discovered that Lockwood outranked Ruger. Not wanting the 1st division to be commanded by an officer whom he did not know, had never worked with, and whom he considered inexperienced for the job, he retained Lockwood's brigade as an "independent brigade" reporting directly to the commander of the 12th Corps (Williams). Thus, Ruger continued to command the red star division.

Once Slocum took command of the 12 Corps back- after giving up his "wing command" position- Williams returned to the 1st division, and the awkward command arrangement was terminated. Lockwood then became the 2nd brigade of the 1st division of the 12th Corps.

I believe this should answer your question.