Yes, I am a former Mi Tech student. While there I wanted to be somewhere else. Now that I am gone I really miss the UP. It really is kind of a unique place. I even miss the snow sometimes. 0.5" of dirty snow in Joliet does not yield much of a Christmas feeling quite like the piles of fluffy fresh snow we got in Houghton. After Christmas though, I dont miss all that snow
Lots of things to do in Peoria as far as I can tell. I would say there just is not as many simultaneous events. In Chicago on any given weekend, there are probably 5+ major events and many smaller ones going on somewhere that you could choose to go to depending on your interest. In Peoria, there would be more like one major and a few small events happening each weekend. For example this weekend is Oktoberfest, hosted the the Peoria German society. Just got back from that, polka music and beer are always fun!
Every couple of days in summer they have concerts down at the waterfront on the CEFCU stage (Cat Employee Fed Credit Union). You just probably wont find headline bands down there though, but I am sure they are still fun. I think there are plenty of bars to hop around to if you like that. I just found there are several nice areas for mountain biking which made me happy. I am sure you can just hike many of the trails too. Lots of guys/gals like road biking down here. There are some small hills around here to make riding a little more fun. See here for biking:
There are several historical sites I am sure. Check out the events and community tab on Peoria.com. The Peoris.org site has lots of good info too. There is also the Peoria Civic Center which has plays, ballets, concerts, etc. Lots of farmer markets go on all summer with lots of good veggies fruits and other things. There is the Par-A-Dice Casino here too if your into that.
I do not think there is any amusement park here. But Six flags in Chicago or St Louis are not too far away. There is a zoo here if you have kids, but I have not been there yet.
Not sure what else to tell you as I am kind of new here myself. I think the peoria.com and peoria.org would be good places to start. If you have any specific questions, I can do my best to try to help.
Lots of people do boating as we obviously have the river right there. I get conflicting stories on whether it is ok to swim in the river. Some say no way, others say it is fine to waterski/tube in, just dont drink it. I assume the official government line is that it is ok to swim in, since people do it.