I wrote a vim function to help me navigate the wiki when I'm editing it. It extends the 'gf' (goto file) functionality. Once installed, you place the cursor on a wiki page name and press 'gf' (without the quotes); if the file exists, it gets loaded.

This function takes into account the ikiwiki linking rules when deciding which file to go to.

let me know what you think

To enable this functionality, paste the code below in your `.vim/ftplugin/ikiwiki.vim` file

    " returns the directory which can be considered the root of the wiki the
    " current buffer belongs to, or an empty string if we are not inside an
    " ikiwiki wiki
    "
    " NOTE: the root of the wiki is considered the first directory that contains a
    " .ikiwiki folder, except $HOME/.ikiwiki (the usual ikiwiki libdir)
    "
    " if you can think of a better heuristic to get ikiwiki's root, let me know!
    function! GetWikiRootDir()
      let check_str = '%:p:h'
      let pos_wiki_root = expand(check_str)
      while pos_wiki_root != '/'
        if isdirectory(pos_wiki_root . '/.ikiwiki') && pos_wiki_root != $HOME
          return pos_wiki_root
        endif
        let check_str = check_str . ':h'
        let pos_wiki_root = expand(check_str)
      endwhile
      if isdirectory('/.ikiwiki')
        return '/'
      endif
      return ''
    endfunction
    
    " This function searches for a .mdwn file (<a:name>.mdwn) using the ikiwiki
    " WikiLink rules and returns its full path.
    "
    " The rules are the following
    "
    " if the filename starts with '/', use as base dir the root directory of the
    " wiki
    "
    " if not:
    "
    " try first ./<bufname>/<a:name>.mdwn
    " then for  ./<a:name>.mdwn
    " then for  <root_of_wiki>/<a:name>.mdwn
    "
    " return the first one that exists
    "
    " the base path (. above) is the directory that contains the current buffer
    "
    function! FileForWikiLink(name)
      let target_fname=a:name . ".mdwn"
      let wikiroot_dir = GetWikiRootDir()
      if match(target_fname, '^/') >= 0
        return wikiroot_dir . target_fname
      endif
      let subdir_file = expand('%:p:r') . "/" . target_fname
      let currdir_file = expand('%:p:h') . "/" . target_fname
      let wikiroot_file = wikiroot_dir . "/" . target_fname
      if filewritable(subdir_file)
        return subdir_file
      endif
      if filewritable(currdir_file)
        return currdir_file
      endif
      if filewritable(wikiroot_file)
        return wikiroot_file
      endif
      return a:name
    endfunction
    
    setlocal includeexpr=FileForWikiLink(v:fname)