Re: Lumpy yard what is the best way to fix it
1) Rent a sod cutter and remove all the sods. (makes a great compost once rotted)
2) Bring in truckloads of topsoil or garden soil and carefully fill the low spots.
2a)If necessary because of large size and bad material, York rake it to get the debris out.
3) lay new sod on the level lawn, or seed it. In the northern hemisphere we are just getting past the season where seeding or sodding is water-effective, as the summer sun will undo your efforts at irrigating. Wait 'til fall.
Remove not the ancient landmark, which your fathers have set.