Using a smartphone as a hotspot works. This is exactly how I am using mine when away from home. My Samsung Galaxy phone is used as a hotspot for my laptop and for a Raspberry Pi2B with the Edimax WiFi dongle. Most of my music is on my laptop, some on a flash drive plugged into one of the Pi USB ports. The WiFi dongle is plugged into another USB.
I would not describe my setup as portable by todays standards though. Luggable, maybe