My lawn looks like crap. I see three problems--weeds, ant hills and bare
spots. So I want to kill the weeds and the ants, and get grass to grow in
the bare spots. I don't really need a perfect looking dark green lawn, but
no weeds and good grass coverage would be nice.

Some of the bare areas are beneath a few large oak trees. I've heard that
it's really tough to get grass to grow under trees, so I'm either taking the
trees out or just put up a border and mulch around the trees.

Another problem (I think)--two different kinds of grass in my yard. The
prior owner planted zoysia on the side of the house, which gets a lot of
sun. The rest of the lawn (sun and shade exposure) is (I'm guessing) some
kind of rye/fescue blend. Do I need to treat the zoysia differently as far
as fertilizing, weed killer, etc.?

In what order should I work on the lawn? Weed killer now, then ants, then
wait 'till fall to put seed down? I'm in the Philadelphia, PA area.