I have been training again for about six months after six years of periodic starts and stops. Worked on my cardio, worked on my strength, worked on my cadence, and finnally am working on the endurence. Recently I ran a 2:45 20 miler on mostly hilly, gravel roads. I was sore that day, but after a day off I was able to do a quality speed workout. My question is: should I pace with a pace group at 3:30, and try to negitive split the last 8 miles, or go my own pace slightly faster than the pace group. I would really like to get a Boston Qualifying time (3:24), but am afraid of a major bonk. In anyones opionion, How does gravel to urban street pace times compare? And does anyone have experience with pace groups? I usually run by myself, and have a pretty good feel, now, of my effort vs. heart rate on uphills and down. The pace group info said he would run an effort based pace....same effort throughout. Am I crazy to think that I could run a 40 min 10k at the end of a Marathon? Or wiill my pace be higher based on rest and pavement. I do have one more 20 miler training run planned. Do I try to simulate my pace on that run as well? It has been six yrs since my last marathon and I shorted my training on that one(16 wks), got runners knee and gutted out a run/walk of the last 3 miles. 3:52 finish time. Any info would be of help. or just let my know how you are going to approach your goal race.