  We probe the neutral circumgalactic medium (CGM) along the major axes of
NGC891 and NGC4565 in 21-cm emission out to $\gtrsim 100$kpc using the Green
Bank Telescope (GBT), extending our previous minor axes observations. We
achieve an unprecedented $5\sigma$ sensitivity of $6.1\times 10^{16}$ cm$^{-2}$
per 20 km s$^{-1}$ velocity channel. We detect HI with diverse spectral shapes,
velocity widths, and column densities. We compare our detections to the
interferometric maps from the Westerbork Synthesis Radio Telescope (WSRT)
obtained as part of the HALOGAS survey. At small impact parameters, $> 31-43\%$
of the emission detected by the GBT cannot be explained by emission seen in the
WSRT maps, and it increases to $> 64-73\%$ at large impact parameters. This
implies the presence of diffuse circumgalactic HI. The mass ratio between HI in
the CGM and HI in the disk is an order of magnitude larger than previous
estimates based on shallow GBT mapping. The diffuse HI along the major axes
pointings is corotating with the HI disk. The velocity along the minor axes
pointings is consistent with an inflow and/or fountain in NGC891 and an
inflow/outflow in NGC4565. Including the circumgalactic HI, the depletion time
and the accretion rate of NGC4565 are sufficient to sustain its star formation.
In NGC891, most of the required accreting material is still missing.
