"Also stuff to keep snakes away"
Unfortunately, there is not a snake repelent on the market. The best way to get rid of snakes is to take away their food source, so stock up on cats.
As far as weeds, most experts will tell you the best weed preventative is fertilizer and a sharp mower blade. In other words, feed and trim the good stuff and it will eventually take over the bad stuff.
Mowing works well for some weeds, but others like blackberry thickets, it just makes them spread. Privet Hedge is even worse. That stuff is EVERYWHERE around here. You need a bulldozer to get rid of it. And Kudzu is the worst. I think it can survive an atomic blast. They say it makes good cow hay though and one of the ways to control it is to fence it in and turn LOTS of cows on it for a long time and they'll eat it down until it dies.