Tough call. On one hand, you could play a bit conservative, play to your strengths (negative splitting), and pour it on at the end when you hit the hills, possibly surging when the leaders are fading. On the other hand, going with the leaders may just be the extra impetus you needed to shed your preconceived notion of your speed limits. Nothing like a little competition to drive you to new personal bests. Of course, it could also lead to a blowup later in the race.
Maybe look at it this way.....Do you need the positive reinforcement of a good but possibly conservative race or are you ready to hang it out there in a high risk/reward scenario?