Hostelling armor is already a nice thing.
What i really would like to see though is a feat that let´s animal companions and mounts ignore difficult terrain. Maybe only for running or charging. Kind of similar to dragon style, only better and more thematically suited for animals (that will eventually be kept medium too).
While mounted combat can be really strong in some scenarios, in most others it is difficult, especially in PFS and a lot of dungeons.
So some backup to ease that would be very welcome.
For horses there are many amazing magical horseshoes. Something like that for other animals would be cool too.