Well first off, you were able to ride 100 miles. That's the hardest part--just going the distance. So congrats! Secondly, 6-hours and 10-minutes on a paved path where you had to slow down for people is a really good time, definitely above average. As far as training, doing some form of interval work during the week (there are tons of websites and books out there) mixed with relatively longer rides on the weekends (50-75) will help you stay faster for longer. The interval work will also help you do real racing if that's what you meant. One thing that helped me the most is finding a regular group ride near you. That will help get you out consistently, you'll meet other riders and pick up tips, and it's more fun than slogging along by yourself all the time. It'll also open a whole other world of rides that are word of mouth only, and guys that want to try their legs out in different parts of where you live. But you're off to a really great start. I hope you'll post more about how it's going.