Before euthanasia

My 17 years old dog 'Boira', is gonna have to be euthanised soon. She can barely walk, her body can not keep up any longer. I want her to enjoy her last days and experience all those things that she couldn't before.

Any ideas on what to do? What food should I give her? (Chocolate, burger...) Places to take her one last time? (Sea, mountain, park...)