I probably qualify as a subject matter expert on the state line.
Are you planning on attending the meet, and do you have any ideas for Brandon? I'm sure he'd be open to hearing them.
We're far enough out that other ideas are fully welcome. 
I've never ventured out to the state line marker, so that will be new for me.
I'm sure some of these will be more interesting than others, but here's what I have:
1) The Horseshoe Hammond casino was opened in 1996. At the time, there were no casinos in Illinois so it was hugely popular. Illinois has since allowed casinos but the 'Shoe still does good business.
2) Hammond and Munster number buildings on N-S streets using the same system as Chicago/Cook County but subtracting 10000, so along State Line Rd in Hammond/Munster/Calumet City/Lansing the numbering of the oppposite sides of the street are off by 10000.
3) Due to real/perceived issues with crime, Hammond split State Line Rd south of 165th St/River Oaks Dr, so that there are no through streets between 165th and the River. The Hammond side is one-way north, the Calumet City side one-way south.
4) On nearly all of the non-highway border crossings, there is no signage to indicate the border. Of course the name State Line Rd is a giveaway for the spots where that exists.
5) There are two businesses where the building buts right up against the state line on the Indiana side with some of the parking lot in Illinois--Strack and Van Tyl's supermarket at 12 Ridge Rd in Munster and Franciscan Hospital Dyer at 24 Joliet St in Dyer
6) There are three new commuter rail stations that will be part of the new Westlake branch of the South Shore Line. There has been some demolition of homes and utility work, but nothing terribly visible yet. These sites are at 400 173rd St in Hammond, 400 Ridge Rd in Munster, and 500 Sheffield Ave in Dyer.