  We study the distribution of the interstellar neutral (ISN) gas density and
the pick-up ion (PUI) density of hydrogen, helium, neon, and oxygen in the
heliosphere for heliocentric distances from inside 1 au up to the solar wind
termination shock (TS), both in and out of the ecliptic plane. We discuss
similarities and differences in the large-scale structures of the ISN gas and
PUIs formed in the heliosphere between various species. We discuss the
distribution of ISN gas and PUI densities for two extreme phases of the solar
activity cycle, it is the solar minimum and the solar maximum. We identify the
location of the ISN gas density cavity of various species. We study the
relative abundance ratios of Ne/O, H/He, Ne/He, and O/He for ISN gas and PUIs
densities and their variation with location in the heliosphere. We also discuss
the modulation of relative abundance ratios of ISN gas and PUIs along the TS.
We conclude that the preferable locations for detection of He$^+$ and Ne$^+$
PUIs are in the downwind hemisphere within 1~au, whereas for H$^+$ and O$^+$
PUIs the preferable locations for detection are for distances from Jupiter to
Pluto orbits.
