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.
WTF You are just a heartless Bastard even to think of just letting her go. Abandoning her at the last moments of her life and if you're so cheap to have to discuss this maybe we can take up a fund for you.