This looks like an ideal hot tube setup for a tiny house on wheels. It packs up quickly and takes up little storage space. The thermosyphoning heating coil can heat the water with a propane burner to 105°+ F in 2 1/2 hours from 60-70 ° F. The tub and coil are sold as a separate units.
I’ve not had a chance to experience this hot tub personally, but I once owned a wood fired redwood hot tub with similar performance – and loved it. A redwood tub is far less portable – so this would seem like a better option for mobile tiny house living. Learn more about the Nomad Collapsible Tub and Heating Coil.