The First to Take his Leave

[addy]

I’m going to be the first
To truly take his leave.

I will not flirt with the idea-
Clouds hang over earth (I might be completely mistaken here, but if I'm interpreting your analogy correctly them imo "hang" is not the perfect descriptor to drive home the intent... I know you've already used "floating" somewhere else, but maybe another word that implies more of a distance or disconnect from the ground. Just a suggestion)

Only to pour down, but I-
I’m going to be the first. (personally wouldn't have finished the couplet with this line since at this point it's already slightly detached from the point of what you're saying... which is unlike clouds, you will neither hesitate nor fall back)

I’ll never clutch a walking-staff (I like how "clutching" the walking staff reinforces your idea)
Down some barely-beaten path

Tend a fire in the woods- (Not sure if this line helps in particular, but still nice)
Leaving people does no good.

It fails (Not sure what this refers to?), but I will be the first
To truly take his leave.

No, not with nooses, needles,
Magic carpets, sex, or rockets

But by the buoyancy (can this be just "buoyance"?) of loneliness. (I admit I truly love this line, but I can see how it's a bit telly)
Like a string-cut, transparent balloon

Pitied (Not sure if this descriptor fits, or is necessary), set free, floating slow-
Along its empty, vertical road. ( I really like how this parallel's the barely-beaten path)

I will not pop, but go
And go...

I will be the first
To truly take his leave.

Needs just a few tweaks to make its beauty truly shine, but I see what your getting at here and I love it. Sounds positively zen.