Hey There BBECK dont get discouraged, I started at 380 and After 2 years of riding I am at 310 and rode 4000 miles last year and 8 of them were century rides. I can ride with some of the big names here in my local bike club and they cant believe that I can ride as well as I can for someone my size. Just remember that people our size have an awesome amount of power. the little guys can only dream of being that strong. I too started with a loop around my house that was about 5 miles and when I got home I could not move. Now I look at that loop and say that I am not even warmed up at 5 miles
Before long you will be doing laps around that block and wanting more. Just stay with it. ~E