Getting to Sharon's Wedding:
Rand McNally is your friend.  If you don't already have one of their Road Atlas books, go get one right now.
Because Valparaiso does not have a commercial airport.
You *can* fly into Chicago and arrange transport; there will be more details on that further down the page.
Right now I'm just talking about getting there on the ground.

Northeast Illinois  NW Indiana Hwy 49
Folks coming from the east have it the easiest: Indiana Hwy. 49 crosses all three of the major roads (US-30, I-94, I-80/90) coming from that direction.
Folks coming from the southeast will probably be on I-65: you'll need to turn east onto US-30 at Merrillville.

Folks coming from more directly south will probably be on I-57. I do not recommend going all the way north to US-30 before turning eastward.  This would get you into Chicago Traffic, and not in a very pleasant part of town, either.  Turn east at Kankakee instead, onto Illinois Hwy.17 (Exit 312). Follow that road east to Momence, then turn onto IL-114 (which becomes IN-10 when it crosses the state line).  Follow IN-10 to I-65 and turn north toward Merrillville.
Yes, that IS a John Deere tractor on top of the silo a little before you get to the state line. tractor on silo
  
If you happen to be coming in on I-55, you need to shift to I-80 eastbound just before you get to Joliet. You won't be able to avoid the little bit of I-294 toll road, but that will end at the state line.  Once in Indiana you want to stick  with the I-94 signs, because I-80 joins-up with the I-90 toll road shortly after the I-65 junction. Even if you DO get trapped onto the toll road,  it has an exit for IN-49.

If you are flying in to Midway or O’Hare airport, you can get to Chesterton via commuter rail connections pretty-much at any hour of the day.  From O'Hare, the Chicago Transit Blue Line train runs at least every 15 minutes into the Loop; from Midway the Orange Line runs about every ten minutes. Either train will cost you $2. Get off at the Washington Street station, hike two blocks east and one block north to the Randolph Street Station to catch the North Shore Line to Chesterton.  These trains depart about every hour and a half from 8:45 a.m. to midnight:45 and cost $6.65 for as far as Chesterton.

The airport shuttle bus company does not go to the Chesterton hotels; it only goes to Merrillville, and it costs a LOT more than the trains anyway.
And of course, both airports have desks for all the usual /s/u/s/p/e/c/t/s/ car rental companies.