In my new book I do not use the term "connector holes" very often, except for the first course -- High Pointe.
At High Pointe, the 13th hole was the connector on the back 40 acres, after I had found #12 and #14. On the front nine, it was the 7th, after I'd decided on a position for #8 tee. And I learned that by making good decisions in planning and shaping those holes, they might wind up among the best holes on the course . . . so, since then, I have rarely used the term "connector hole" because it sounds dismissive, and sometimes they are the most important holes of all.
Every routing involves making a bunch of connections -- in a sense, every hole is a connector hole. But which you identify as such depends on how you approach the routing and which holes you find first.
For example, the most important hole at Rock Creek is the par-4 7th. That's the most rugged piece of ground we had to get through, and because we were trying to get to the tee of a par-3 to play across the stream, I couldn't build two par-3's before that to traverse the terrain -- I had to find a longer hole. But, because I identified the problem right away, that was actually one of the first holes I found on the map. [The very first hole was #10 -- and that was how I knew I had to get across the creek up in that vicinity.] So, I would say #7 is a connector hole, but it's actually one of the first holes I set in stone.
By contrast, at Ballyneal, we identified the 8th hole pretty early, and the 7th was a connector to get to it -- you had to come over/around that little ridge to get to #7 tee, and then the green had to be close to #8 tee. Originally we had the 7th green up near where the 8th tee is now, and the 8th tee further over, but the view on #8 through that little slot to the left was much better with the tee where it is, so I went looking for a different green site for #7 . . . and it turned out alright.
Routing is full of little puzzles like that, but a lot of times it will be hard to tell from the outside which piece came first, because you don't know what will have drawn the architect's eye. The book attempts to explain what I saw first.