The temperature dependence of the resistivity, ρ, of ceramic La _1-xSr_xMn_1-yFe_yO₃ (LSMFO) samples with x = 0.3 and y = 0.03, 0.15, 0.20 and 0.25 (or simply #03, #15, #20 and #25, respectively) is investigated between temperatures T ∼ 5 and 310 K in magnetic fields B up to 8 T. Metallic conductivity in #03 is changed eventually to activated in #25. In #15 and #20 the behavior of ρ(T) is more complicated, comprising of two extremes, divided by an interval of metallic behavior in #15, and two inflections of _ρ(T) in #20 within similar intervals ΔT below ∼100 K. Mott variable-range hopping (VRH) conductivity is observed in #15 above the ferromagnetic Curie temperature, T _C. In #20 the Mott VRH conductivity takes place in three different temperature intervals at T > T_C, T close to T_C and T < T_C. In #25, the Mott VRH conductivity is observed in two different intervals, above and below T_C, divided by an intermediate interval of the Shklovskii-Efros VRH conduction regime. Analysis of the VRH conductivity yielded the values of the localization radius, α, and the dependence of α and of the density of the localized states, g, near the Fermi level, on B. Above T_C the localization radius in all samples at B = 0 has similar values, α ≈ 1.0-1.2 Å, which is enhanced to α ≈ 3.3 Å (#20) and 2.0 Å (#25) below T_C. The sensitivity of α and g to B depend on y and T. The complicated behavior of the mechanisms of the hopping charge transfer, as well as of the microscopic parameters α and g, is attributable to different electronic and magnetic phases of LSMFO varying with temperature and Fe doping.