A.C.
I really think you should hire a pet-sitting service. It is hard enough on many indoor cats who are used to being indoors, for them to be boarded---it would probably be a miserable, traumatic experience for this cat, who is an outdoor cat.
If you don't have a good friend or neighbor you can ask, hire a pet-sitter, and just explain the circumstances to him/her about the cat's personality and background.