Before I ask my question let me apologize if this is not the appropriate site for personal assistance, as opposed to questions regarding landscaping businesses. I need assistance landscaping my mom's back yard. Currently it is full of grass up to mid-thigh with spots of dirt that seem to have come out of nowhere. Also the terrain is not even with dips throughout the yard. My main project is to level out the back yard as it currently has a big decline from the house to the fence. Someone told me to buy some grass killer and then maybe use a tiller dig up the dirt and level out the yard. Is this a good plan? Should I consider anything like permits, neighbors, etc? Attached are pictures of the house. I don't have the size of the yard. Btw, I currently have Toro Super Recycler and she wants to use it back there but I think the uneven terrain would damage it. Thank you all in advance for your help.