I've been using the route regularly (annually or more often) for the past 12 years, between I-55 or I-57 and Logansport, sometimes all the way to Fort Wayne.
Hitch I have encountered the past two years has been long detours around long short sections where they've been working on 24. First was just west of US-41 in Kentland, detour was taking me so far south on 41 that I just started using Indiana-26 and Illinois-9 as a alternate route to I-57.
Last summer there was a long detour around something they were doing between Reynolds and Monticello, then the detour had a detour. So next couple times through I just took US-421 north and connected with I-94 in Michigan City.
I once split the difference between the two Interstates, took Illinois 54 from US-24 to Springfield. That was straight, light traffic, but tended to be rough pavement and slow going with lots of small towns, seems to parallel an old whistle-stop line that produced market towns every 10-15 miles.
Can't say anything about the US-136 plan, haven't tried it. I took US-24 all the way from Logansport to Quincy once, won't do that again, there was too much rough road. I usually take I-57 and I-72 through Illinois to Hannibal, that gets close to Quincy. I'll take I-55 (which tends to be much busier with more bad driving) only if I know there is extensive construction on I-57.
Tom Test
Itasca Spirit 29B