Apparatus and methods are provided for providing access to a body lumen. The apparatus includes a tubular member including a proximal end, a distal end sized for insertion into a body lumen, and a lumen extending between the proximal and distal ends. A pushable stiffening member extends from the distal end of the tubular member, the elongate member terminating in a distal tip. An expandable sheath extends along at least a portion of the stiffening member, the sheath being expandable from a contracted condition to minimize a profile of the sheath to allow insertion along with the stiffening member into a body lumen, and an enlarged condition wherein the sheath at least partially defines a lumen communicating with the tubular member lumen. In one embodiment, the sheath includes an outer lumen and an inner lumen floating within the outer lumen, and the stiffening member is carried in the inner lumen.