On Wednesday, proceeding to Danville and then exiting to drive US 150 all the way to the Quad Cities. From there, I-280 to US 61 to Muscatine, where I will take IA 22 west to pick up Washington and Keokuk counties, then back to US 218 north, which I will take all the way to Waterloo. I think I should be able to make it to Waterloo, if not farther, on Wednesday for the night.
My gut instinct here says you're biting off more than you can chew. Danville to Waterloo via Muscatine and South English
via I-74 is 7 hours/400 miles according to Google. US 150 will bog you down in four different cities especially Peoria. Then, if you're going to Keokuk County, it's faster via a series of county roads and IA 21 than going back to 218. (If you need 218 without 380 and 30, then South English to Van Horne is a straight enough shot.)
From there, I'm going to continue on along US 218 beyond the end of I-380 to pick up Bremer and Chickasaw counties, then east on IA 346 at Nashua to US 63, then south on US 63 and east on IA 3 to pick up Fayette County. Then south on IA 150 to get Buchanan, east on US 20 to get Delaware, then south on IA 38 to snag Jones, then US 151 north to Dubuque. From there, US 52 north gets me Clayton, Allamakee and Winneshiek counties. I'll have to go west on IA 9 to get Howard County, but then return to US 52 for the clinch in Iowa. I'm pretty confident that I can get farther than Rochester on Thursday, which was my goal, so I'll probably stay somewhere along I-90 between US 52 and the South Dakota line.
First bad news:
Half of IA 346 is closed. If you're set on getting Chickasaw but not 218's miles, better to do US 63-US 18-V56-IA 3, or four-lane 63 up and back. Otherwise from Nashua you'll need to go back to IA 188. Also, if you're going for clinching US 52 in Iowa, consider
it will be rerouted in Dubuque County in about three years, taking it off the slowest most winding part.
This also seems ambitious to me especially with taking US 52 through the Driftless Area (of course, I'm saying this to someone who drives mountains all the time, so...). On the other hand, Google comes up with 8 hours/400 miles Waterloo to Rochester via your path (replacing 346 with 188).
I can see from your county map that you're trying to close up your hole in eastern Iowa (an admirable goal

) but at the same time you're going directly at the not-straight part of Iowa. I can game out quite a few possibilities that I think would be better/faster but only hits maybe eight of those 11 counties and/or loses US 52 (and it also makes a difference if Waterloo has to be the starting point or if Cedar Rapids can).