Use the 'gf' shortcut. Move your cursor on the beginning of a path and then press gf in command mode, or Ctrl-o gf in insert mode. GF stands for "goto file". From help gf:
Uses the 'isfname' option to find out which characters
are supposed to be in a file name. Trailing
punctuation characters ".,:;!" are ignored.
Uses the 'path' option as a list of directory names
to look for the file. Also looks for the file
relative to the current file.
Uses the 'suffixesadd' option to check for file names
with a suffix added.
If the file can't be found, 'includeexpr' is used to
modify the name and another attempt is done.
To get back, use Ctrl-o in command mode.