A gateway is when one program runs another program. Gopher can 'run' telnet, but you are then in telnet, rather than gopher, and you don't have the gopher menus. You are 'dropped back' into gopher when you leave the telnet session. Gopher is not just a set of ftp sites. Some gopher sites are not ftp sites.
Different gophers can talk to each other.
Each gopher can 'point' to areas on each other gopher. Gopher is a way of providing information to the net and a way of organizing the information that the net provides. Veronica is a way of searching gopher, and is only available from inside gophers. Veronica can be used in two ways. It can look at all items in gopherspace, or only the directories in gopherspace.