I'm glad you're considering UW for undergrad!
Very few people actually go through with being pre med after their freshmen year and an even smaller number (1/4-1/5) people are still pre-med by the time they reach senior year and apply. That's just reality at every school. People come in thinking they'll ace gen chem and can't handle chem 103/104, let alone those who suffer through 109. It is very hard to get A's in the large science prerequisite classes here. In any given science class, about 10-20% of the class get's an A so you have to be one of the top student consistently in genchem, ochem, physics, bio, plus upper level bio classes.
It is very easy to get research positions here. There's the Undergraduate Research Scholars Program, contacting professors on your own, or the student job center website.
Most pre-meds here are very friendly. We have about 6 large premed/pre-health organizations so you'll always have pre-med friends. Most pre-meds here aren't gunners but a few I know are cocky as hell. The professors here won't get to know you unless you make the effort first.
Madison has so much to do, from research, student orgs, campus & residence hall events and activities..you name it and you can do it!! There's no shortage of volunteer opportunities at UW and the Morgridge Center for Public Service does a great job too. If you need more help in deciding or if you end up coming here, PM me for more guidance!
P.S. I'm heading to UW's med school in the fall so I know what I'm talking about.