I'm about in the same situation. I am going to brush hog my newest plot (#3) as soon as the snow is gone to stimulate the brush and weeds to start growing and then I will spray it with Roundup. I've done this before and it seems to work OK. I started a plot last winter (#2) by burning a slash pile of old dead tree limbs and brush. I then brush hogged it and got out the Roundup next. I kept spraying the newly emerging weeds as the came up. I have alot of weeds around my area so I'm waiting until late this summer to plant just to make sure I've killed all of the weeds and brush. I'm planning on planting annuals for a couple years just to make darn sure the weeds and grasses are totally gone. I didn't do this to my first plot (#1) and it is full of weeds and grass. I'm going to spray plot (#1) with a grass killer this spring. I might need to totally kill it the following spring and start over depending on how it looks next summer. I planted clover in it and the first year it looked pretty sad but last year it grew really well. The grass and weeds that I didn't kill the first year have started to invade pretty heavily. I have also used 2-4D Herbicide and some Tordon to kill some of the really nasty weeds that Roundup doesn't kill. Just remember, some chemicals just burn the plant down but doesn't kill it and some totally kills it. It just depends on how tough the weeds are.
GoodLuck I hope some of this had helped. I am still learning as I go so I'll keep your informed how mine our doing and keep us posted on how yours is doing.

ArcheryElkDude[8D]