Dennis Cycle Center is right on the Rail Trail. They have a plentiful supply of bikes and equipment for sale. Also a great place to stop if you need a repair, they have a full service repair shop. Whether you need a full tune up, or just have a flat: their staff is experienced and knowledgable .  They rent road bikes, hybrids, comfort bikes, kids bikes, tag-a-longs and babyseats and E Bikes.