The "No Logo Signs" is a bit of a chicken and egg problem -- Pretty sure the reason there are no Logo signs for Food and Fuel is because of the Oases...
The Hampshire/Marengo/US 20 exit on I-90 is a free exit, and it is a pretty standard Truck Stop and Fast Food type stop, plenty of options.
IL 47 exit is a free exit on I-88, as is I-39/US 51 and IL 251. IL 47 is a bit of a tough one for thru traffic, due to a couple miles between the West facing Exit/Entrance (actually on IL 47, due North of Sugar Grove) and the East facing Exit/Entrance (Northeast of Sugar Grove, also is the "Old" Tollway ending, and the stub end of IL 56 leading to the US 30/IL 47 junction in downtown Sugar Grove). IL 251 has at least one Gas Station, right off the exit
I bet DeKalb would beg to have the toll lifted at Annie Glidden Road, if they could develop Annie Glidden to be a Truck/Services Stop, which they don't have a market to do as long as the Oasis is there AND having the Annie Glidden Exit tolled
The Dixon exit on I-88 is free -- used to be tolled in one direction, but not anymore. That exit is pretty much a typical Interstate-type Food and Fuel/Services Stop, and distance-wise, is about the distance a 2nd Oasis on I-88 could/should have been from DeKalb
ISTHA and the towns that the Tollways flow thru, even the rural parts of I-90 and I-88, would adapt and provide the motorist services that the Belvidere and DeKalb Oases do today