Very modest 100 freestyle goal--tips appreciated

Hi all, First off, my 100 free is such that Michael Phelps could do a 200 and towel off before I finshed my 100. And good on him! But I am planning to swim this event in my local Senior Games meet next week--and just want to break 2 mins. Yes, I can swim long--but not fast. That sub-2 time has been an elusive goal (granted I put more time into running last year than swimming, so got somewhat sidetracked... a running injury, however, has served to refocus my attention on swimming). Fortunately, my 100 times have started to improve, so that in recent workouts, I have them down to 2:01-2:02. My thought is that with a dive start, I can drop a couple seconds. My masters' coach said maybe I might even consider aiming for 1:50. But I've been known to over-reach at the start and blow up in the last 25, so I want to be careful about this. I'll see how I feel on race day, of course, but I welcome any tips you might have. Again, admittedly, this is modest. Discreet laughter permitted along with tips. ;)