A Leapfur is a riding animal, resembling a large kangaroo. When April asks how Na'ane escaped Marcuria and the Azadi, she replies "As a stowaway on a tradeship bound for Corasan, and on a leapfur's back north along the old paths. A Zhid was generous enough to share her mount with me." Presumably the leapfur was the aformentioned Zhid's mount.
In an early trailer for TLJ two figures are seen riding large, bounding animals. Presumably April and a companion were originally intended to use this as a form of transport.