Here's what I do if I'm traveling (this is all in a v-scanner folder, separate from my every day at home folder). I have each interstate as a system, and also as a scanlist. For example, my scanlist 1 is Chicagoland (all the simulcast sites in the counties that surround the city), 2 is I-39 and 90 combined (not a lot of sites between them, so I consolidated), 3 is I-88, 4 is I-80, and so on and so forth. They're all their own individual system. Then I programmed in all the ISP district channels that whichever road goes through. This way I don't have to fool with a wildcard while I'm driving and don't have to figure out what something is on the fly either. Whenever I switch roads, I just have to simply switch scanlists. If you go with that method and program one scanlist for every (major) interstate in Illinois (and combine 39 and 90), that'll take up 11 lists. I have one for statewide channels (ISPERN, IFERN, I-REACH, etc.), one for CPD, one for St. Louis, one for Rockford, one for the Quad Cities, one for Peoria, one for Bloomington/Normal, one for Springfield, then finally one for US 20 west of Rockford. I'm also in the process of putting all the sheriff departments that are available in my favorites list, to make them easy to access if I need to. For all the StarCom sites, just make a list of all frequencies used by the towers along whatever road, put them all in as control channels and set multi-site to roam. I've made many trips throughout the state using these settings and it works great for me.
A bit long, I know, but that's my method.