Perfect relaxing ride with friends, kids and beginners will be fine.

You can ride on a trail from the bus station on Congress street, over the bridge, down Commercial St. (a bit of traffic here to worry about and road is not in great shape, but most of it is wide, 2 miles) then through the old port onto the paved path that runs along the water next to the narrow gauge rail. You follow along the harbor, great views of the islands and cooling breezes, up a hill past the sometimes stinky water treatment plant and back down (3 miles) where you can continue to circle around back bay (3 miles). This is a simple ride for a beginner or kids, just 2-3 hills to challenge you. The hardest one is near the water treatment facility. If your get tired just do not continue on to the loop around back bay.

This is a trail for cruising, not racing, as there are skaters and runner/walkers. Start and end where you want to alter the length.
Along the trail there is a boat/canoe rental facility if you want a break from biking. There is a Park/boat launch on the trail and Back Bay also has grassy areas for picnics.

Best parts of the ride; the views, the option of a great meal, bar hopping, or shopping, in the old port. Both Whole Foods and Trader Joes are easly accessable from Back Bay for a quick snack or picnic and they have bike racks to lock up. There are plenty of posts to lock to in the old port and racks at a park at the top of Exchange St. To date our bikes have been safe and in the day we often leave our lights etc in place.

Eastern Mt sports (open sunday) is located next to Trader Joes if you need emergency bike supplies. Also in the area is Back Bay Bicycle Forest Ave north of Hannaford and Cycle Mania (open sunday), Federal st & India, nearer the east end, Gorham bike, on Congress west downtown and Velociped (off commercial st-nearer west Old Port/bridge).

Remember you are on the water and the weather can be cooler than inland.