My pre-shot routine starts about minute before I actually hit the ball. First I look at the lie I have. Next I look at what's in front of me, and where I need to land the ball for an easier next shot. I gauge the distance needed , and pick my club. I step into my stance , give the club a couple waggles, and then hit the ball. I pick up my tee, or fix the turf as needed, and go on my way to my next shot.
When putting my pre shot routine "casually" starts while I am walking up to the green. I get a better visual of any hills, or valleys associated with the green from a distance.. If I'm golfing with some one, and have a chance to watch their ball roll that's also part of my pre-putt routine. While waiting for my turn, I read the green as needed. I walk up to the ball, pick my aim point, and stroke the ball over my chosen aim point, which is about a foot or so in front of the ball.
Between any pre-shot/pre-putt routine I am usually not thinking about golf. On average, in a 3.5 hour round (210 minutes) I probably only have golf shots/putts on my mind for 1.5 hours (90 minutes) give or take a few minutes. Plus I never think about my last shot. All the previous shot did was set up my next shot. Good, or bad, that last shot was a done deal,
As for my pace of play, I tend to do things quickly. It matters little what it is. A good example would be the other hobby I have which is desert southwest hiking. I tend to walk at a not so fast pace. The pace I walk/hike at suits me quite well, which allows me take in the sites, and not step on anything that might other wise cause me grief. Twisted ankles, slips, falls, and western diamond backs readily come to mind. This hiking pace is also my walking pace on a golf course. My walking pace dictates how fast I play, and has a lot to do with how fast I swing a club. My own timing barrier if you will. My point is that everyone does things at their own normal pace in every day life. . If they deviate from their normal pace, in their golf game, they might not play as well as they could.
As for slow play. It's just another part of the game, just as much as balls in divots, and one putts. Golfers should not let slow play dictate how they play the game. Besides, how many time does a golfer actually run into slow play scenarios............