RE: Shooting lanes...
I don't think it's too late. I've built platforms and cleared lanes a week before the season and taken deer the first day of the season.
The big key is the area you hunt---you have to have the stand in the right place, and hence that's why you're putting this stand up to begin with. Scent actually dissipates rather rapidly, especially if you are taking precautions (like scent-eliminators and cover scents), and is completely gone after a good rain. Disturbing the surrounding environment will have an effect, but very minor if you do only minor trimming.
And I personally feel that it is not the stand that becomes tainted, but rather the route to the stand. Probably 95% of hunters take the same path to the stand every time afield, therefore not only do they leave a "scent trail", but the game notices the pattern and becomes more wary of the area.
S&R