Navigation to certain category subset

[Richard G Riley <rileyrgdev@googlemail.com>]

I have

 (setq org-remember-templates
   (quote (
	   (?t "* TODO %?\n  %u\n %i\n %a\n" "~/org/todo.org" "Tasks")
           (?n "* %U %?" "~/org/notes.org" "Notes")
           (?l "* %U %^{Title}\n %i\n %a\n" "~/org/todo.org" "Linux")
           (?d "* %U %^{Title}\n %i\n %a\n" "~/org/todo.org" "Debian")
           (?e "* %U %^{Title}\n %i\n %a\n" "~/org/todo.org" "Emacs")
           (?v "* %U %^{Title}\n %i\n %a\n" "~/org/vocab.org" "Vocab")
           (?R "* %U %^{Title}\n %i\n %a\n" "~/org/register.org" "Register")
           (?w "* %U %^{Title}\n %i\n %a\n" "~/org/webs.org" "Webs")
           (?r "* %U %^{Title}\n %i\n %a\n" "~/org/todo.org" "Remember")
	   (?j "* %U %^{Title}\n %i\n %a\n" "~/org/todo.org" "Journal")
	   (?L "* %U %^{Title}\n %i\n %a\n" "~/org/todo.org" "Links")
	   (?x "* %^{Title}\n %i\n %a\n" "~/org/todo.org" "Links")
	   )
	  )
   )

Most things stored in todo.org, others in other files.

The sections in the org files are marked with something like:

,----
| * Emacs
| 
| :PROPERTIES:
| :CATEGORY: Emacs
| :END:
`----


But what is recommended way to navigate to "Emacs" from anywhere?

1) from agenda - is "search for keyword" the way to go?
2) from any other location or mode

I'm still a bit at odds as to whether I should be using categories or
just tags to separate things. is there a "jump to category" or "filter
categories" command? I saw nothing in the categories section of the
manual.

Thanks for any advice,

richard.