I commute regularly about 19 miles round trip. I use the weekends for longer rides. i don't think a 35 or a 50 will be too much to handle if you can do some longer weekend rides. Be sure you hydrate and get plenty of ongoing nutrition on the longer rides. As a veteran advised me before my first 50 miler, be sure you leave something in the gas tank for the end of the ride. Pace yourself.