In case you haven’t tried here:

https://www.thelawnforum.com/forums/cool-season-lawns.9/

rifis, just a heads up. Linking to an outside forum used to be the fast-track way to get permanently banned from these forums.

Julian, long time no posts. Are you still in Toledo...because I'm going to assume you are. It helps to remind us when you start a new topic.

You need to get hopping now to get your back yard going. If you do not need to level any of the back yard, then find a fescue variety you like and get it seeded into the back right now. If you have any thatch in the yard, which it doesn't sound like you have that dense of a situation, then pull the thatch first. Otherwise get the seed down and walk or roll it down depending on the size of the yard. If it is small enough you can walk on the seed to press it down onto the soil. The fescue will help with thickening the shady side of the house. Water lightly every day for at least 2 weeks to germinate and establish the fescue.

If you need to level the back yard first, then hop on that right away. You can DIY it for much less than $20k, but it can be some work.

In general, the leveling theory is straight forward.

1. Water deeply
2. Fertilize with an organic fertilizer
3. Scalp the area where the new topsoil is going,
4. Find the high spots and knock them down moving the soil to the low spots,
5. Add more topsoil to the low spots,
6. Use a drag to level and blend the new soil to the old,
7. Water the new soil down to settle it,
8. Allow it to dry and reevaluate the need for more topsoil,
9. repeat steps 5-8 until you are happy with the result.

One hitch you'll find with using topsoil is clods. Anything larger than 1/4" will be a nightmare for you. This is why golf courses and many others will use sand to level. You may need to find an efficient way to smash them down to dust.

The reason to scalp the area where the new soil is going is to make it easier to use the drag. It's hard to level when the grass is tall.

Aeration. Remember back at the golf course when they would bring out the Cascade Plus surfactant? The reason for using that product is to allow water to penetrate through the turf and go deep into the soil. What the homeowners around the country have found is that using a surfactant can replace the need for core aeration. I have to admit I was a skeptic on this topic for far too long. I mean it cost me about 50 cents to try it, so why the delay? I had been working on another way to soften hard soil, that's why. My method works but it was relatively expensive and took many weeks to do an entire lawn. So I tried using baby shampoo instead of the expensive Cascade Plus. It works great! As with organics, the shampoo treatment took 3 weeks to see the benefit. After that the lawn would get too soft to walk on when it rained. So, apply at a rate of 3 ounces of any clear shampoo per 1,000 square feet. Follow that with 1/2" to 1" of irrigation or rain. That's all! There's no way to make a mistake. Morph tried using his homemade surfactant mix at the equivalent of about 64 ounces per 1,000 and applying every week, and everything was fine. I sprayed my lawn in 2012, and we moved away in 2015. The single shampoo treatment lasted those three years at least.

Again, it is late in the Toledo season to get going on this and still reseed. Let me know if I was unclear about any of this.