SQL Server 2012 :: Lowest Child In Recursive Query?

I have following input:

CREATE TABLE #tree
(
Childid varchar(20),
Parentid varchar(20)
)
INSERT INTO #tree
(Childid,ParentId)
SELECT '123' , null UNION ALL
SELECT '456' , '123' UNION ALL
SELECT '789' , '456' UNION ALL
SELECT '870' , '456' UNION ALL
SELECT '985' , '870';

Input:

Child IDParent ID
123 NULL
456 123
789 456
870 456
985 870

I am trying to populate lowest level child with path and depth...Output should be:

Child IDParent IDLast ChildPath Depth
123 NULL 789/123 1
456 123 789/123/456 2
789 456 789/123/456/789 3
123 NULL 985 /123 1
456 123 985/123/456 2
870 456 985/123/456/870 3
985 870 985/123/456/870/9854