I am assuming the sod is a similiar blend. The front has never grown as well as the seeded areas (it's easy to see where the seed stops and sod starts).
I believe part of the issue with the front is that it faces the west so receives a lot of afternoon sun, and in a lot of areas the builder left leftover concrete and asphalt buried just below the surface (I dug up one strip along the driveway and found chuncks of asphalt). The strips along the driveway and the parkway (between street and sidewalk) are almost bare except for weeds during the middle of summer.

I plan on going to an organic program this year with the exception of a first application of crabgrass preventer (corn gluten meal is too expensive). I plan on buying Dimension 13-0-5 (I can't find crabgrass preventer without fertilizer). Is this a good option? I also plan on trying to installing some sort of temporary irrigation system.

How can I ammend the soil in the front to improve the grass growth? I plan on digging up the areas where grass won't growing during summer and removing the concrete/asphalt. What do I do in areas where the grass grows okay but still doesn't do as well as it should (I suspect the soil here might have debris but the area is too large to dig up)? What kind of grass seed should I use in areas where I dig up?

Thanks in advance for any help/suggestions!