I would check at the LBS to see if there are any organized rides for beginners (we have 1 a month) or at least see if there are routes that are already mapped out in the area. I was lucky enough to find a bike group with multiple levels of ability. I live in an area with a lot of retirees so my first ride partners were in their late sixties. They could drop me at anytime but had a tremendous amount of patience with me. They continue to be my biggest cheerleaders. I found that if I added about 10% a week in mileage it went smoothly. Good luck - I have lost 25 pounds since last September and I am sure you will find cycling an excellent way to drop a few pounds.