Where to stay.....if your wallet will allow it stay as close to Campus as possible in South/Bend or Mishawaka. If you want something a little more reasonable but not too bad of a drive try Elkhart or LaPorte going the other way. There is also a decent Holiday Inn Express in Niles Michigan.
I suggest arriving as early on Friday as possible to view the Campus when it is less busy. Take in a volleyball or hockey game that night if they are in town. Trumpets Under the Dome on Friday night or game day, visit the Grotto, Basilica, take a tour of the performing arts centre etc.
There are lots of chain restaurants around....if you like College dive bars check out the Linebacker Friday night...The Mark at Eddy Street Commons is good and for a nice Irish pub check out Fiddler's Hearth in downtown South Bend. There is also of course pizza at Rocco's and many other places.
The key is to walk around campus.....lots of friendly people, visit the book store Friday....it is less busy if you can...or Sunday before you leave.
Enjoy!