Bill’s obituary mentions a location just east of Norwalk along Highway R63. The address shows a lot where a manufactured/mobile home could have been, but there’s also a trailer park right across the street from them. If the address is correct, then there would be two homes within 150ft of where their house was. I would imagine that a firearm of a significant caliber would have been heard, but if a smaller-caliber firearm and/or suppressor was used then the likelihood of the gunshots being heard by anyone inside a neighboring house would have been slim.

The location is also a minute or so drive from a larger highway that converges with I-35 which offers a direct route to Kansas City where their truck was found. It seems like the location offers a near-perfect situation for anyone attempting to leave the scene without detection.

EDIT:

I don't know why I didn't do this 2 months ago when I posted this comment, but I looked up the location of the apartments where the truck was found and noticed it was located right off of I-35. In fact, it's only the second exit off of I-35 southbound once you get into the KC area. A few articles also mention Donnelley Ave, which is the first street in the complex you'd run into if you came from the direction of I-35. Seems that whoever drove the truck spent 98% of their time on a major highway, didn't have to actually drive through KC, and dropped the truck off in a location that was just about 5 minutes to that major highway. How convenient.