  In doped two-leg spin ladder systems, holes are expected to form charged
bosonic pairs. We study charge transport in this system in the temperature
range where the bosons can be described as weakly interacting quasi-particles.
We consider boson-phonon and boson-impurity scattering processes. We suggest
that due to the Ioffe-Regel resistivity saturation mechanism, the resistivity
may exhibit a local maximum at intermediate temperatures. We propose that this
may explain a similar feature found in recent experimental results.
