Hoping to green up a neglected backyard in time for an August 4th graduation party, I spent $1500 on winter tree work to open up the yard to sun. Then a whopper of a sinkhole opened in the yard. $2500 later, the sinkhole is fixed and I don't have a problem with shade anymore...all the trees are now gone. The sinkhole fix added some topsoil to the heavy clay that comprises the yard, and the backhoe/dozer spread it all around. They threw down some seed, covered with straw, and we went to work watering. Some of the yard has started growing (it's been 18 days so far), but I don't have much hope for the rest, approx 3500 sq ft in total. I know I should be looking at all sorts of things that will establish the foundation of a long lasting healthy lawn ... starting with tons of topsoil & organics tilled in. But frankly I don't have the time or money to do it right, I just want to get something/anything that the wife can place her rental tents on. Once the party's over, I'm ok tearing it up and going about it the right way. What's the easiest/quickest/cheapest way to do this? Should I till before seeding, or just keep seeding & ferting & watering away?