I performed this very task on approximately 1 acre the October before last. I removed trees, spread 60 CY of screened topsoil, had a sprinkler system installed (only item I contracted out), aerated, seeded, fertilized, and waited. I now have CONSISTENTLY the best lawn in our neighborhood, even under a dense tree stand.
I don't have a really good picture of entire old yard because it was so fugly, but looking at the ground in the "old yard" picture, imagine that over 2/3 of the acre I'm talking about.
The tools I used: 1 unmodified
BX2230 with FEL, 1 4' box blade, 1 core aerator, 1 tow-behind spreader, 1 standard issue garden rake.
The tools I WISHED I had: 1 York/Landscaping rake. This would have made a HUGE difference in the labor associated with ground roots and final grade preparation.
I DID NOT apply Round-Up to the existing lawn. Don't see a need unless you have a massive weed issue. If you have a few weeds, apply some Scotts...then you'll get some mileage out of the deep fertilizer.
Also, don't think you'll do this and that will be it. You'll have to do 'touch up' later on thin areas or fill areas that settle. Just try and hit the big chunks the first time out.
And use QUALITY grass seed. DON'T GO TO A BIG BOX. Go to a landscaping center and spend the extra on quality seed mixes/blends based on your region and general planting condition (sun/shade). I went to my local "Lesco" dealer. My shade mix cost me $100 a bag...and you can see what it got me. I have never purchased a bag of "Big Box" seed that I haven't been extremely disappointed with.
And I did this in October...probably a month after I should have, but it turned out to be a warm December so all was well. I'd suggest this to be a late September project to ensure good results. Otherwise, I worry you'd be dealing with weeds. And grass doesn't like to do much over 90 degrees.
It is very easy. Feel free to PM me. If you have the tools I stated, you'll get it done very quickly and efficiently. You can try to install the sprinkler yourself, but my guy knocked 9 zones out in 1 day. Couldn't complain.