We present Rb vapor transport through micro-scale capillaries on the impact of temperature and capillary inner diameters in the limits of Knudsen number Kn>>1. Daily absorption spectral measurements were taken over several months to evaluate the dynamics of transport. We provide new insights into the diffusion mechanism and observe a quasi-single-layer coating on the surface based on the analysis of a slowly increasing absorption signal. The dwell time of the atom on the glass is directly derived from the diffusion dynamics at different temperatures. According to the mass flow rate, higher vapor temperatures caused a faster transport speed, indicating rapid loading in microchannels. We provide a valuable model for future quantum device implementation through the use of miniaturized structures such as photonic crystal fibers and optical waveguides.