How do you deal with an 'on the way out' pet?

Thanks for all the sincere replies. I have taken notes from all that was said and come up with my plan.
To preserve the dignity of my 'friend', I won't do Animal Humane or SPCA. You have to 'surrender' your pet first. And I won't ask a friend to do my dirty work. I'm not that schmuck.

I'm going to choose the vet and the two injections. Painless and humane. I doubt if the perfect shot is any better. Then I'm going to bury 'Lily' in the nearby National Forest. Yes I know it's illegal. Arrest me.

I did think about just releasing her into the forest. She is a totally indoor cat. That is why she made 19. Outdoor cats don't live long here. Anyway, releasing her seems cruel, but on the other hand it could be a last taste of freedom. It's tough to reason this out.