Our family did the side-car  type of co- sleeping also. We took the side rail
off of the crib and placed it flush with the bed, carefully filling in the
space between the two matresses. Even after he self weaned at 14 months,
(much to my EXTREME distress) we kept this sleeping arrangement until he
moved to a twin bed at two or three. This way there was room in our bed for
our older two kids to crawl into whenever they needed to, and my husband
worried less about him rolling off the bed when we were not in it. Some time
in the evening I would roll him into the crib, and toward dawn he would
frequently crawl back into bed, if there was room. I think co-sleeping is one
of the USA's biggest kept secrets.

Debbie Rabin, OTR, CLc