As far as the whole "beach" topic goes he prob. feels that he needs to act to feel normal and that is prob. giving him the strength to fight thru his cancer.
The guy probably loves acting more than most other things in the world.
The reason why Chris Walken is in almost every movie is because he says yes to every offer, schedule permitting. He says he loves what he does so much, why turn down an offer of payment to do it.
Side note: The filmed part of an episode of Beast in my condo building. Swayze is still sexy.