「わしもじゃ」
友蔵が出おくれまいと言いそえた。
"Me too" added Tomozou, not wanting to get a late start.
So I eventually figured out that まい was negative volitional (I hope I'm right) then got stuck thinking that と was quotative and couldn't make any sense of it. The context doesn't really fit with him saying that he won't get at late start
I'm now thinking that と is actually making the previous phrase adverbial, resulting in my above translation. Have I got this correct?