This is the 3rd highest peak in WI. However, it has the appearance of the highest. You can see Rib Mountain from over 20 miles away in some directions (from the west for sure) and over 40 miles away from a fire tower near Tomahawk. It also contains the longest downhill ski runs in the state - about 800 vertical feet.
I visited this park numerous times when I lived in Wausau and still do when I'm visiting. I used to run up it regularly, also because it's a good endurance test and it's such a peaceful place. After I moved from the area a new and improved road and paved trail were built all the way to the top.
Often locals park their cars at the bottom to walk up. Some of us try biking - another great workout with a fast coast on the way down. The views are great! The trails are enjoyable. For being right in the heart of Wausau, the park stays relatively quiet - good thing. Even when it is busy it is not overwhelming. If it feels that way, get out on a trail on the southern exposure. You should climb the observation tower. The view is one of the better ones in the midwest. Even the views that are not from the tower are pretty amazing.
Weddings have been held up there - but some have gotten very chili because it's colder up there than at the bottom. There should still be a little snack shop. You can camp there, also. Independence Day advice: don't go up there to watch the fireworks. You end up higher than them and far away, so you don't get much of the effect of them.
You need to pay a fee if you don't have a WI state park pass - unless you walk or bike in.
Overall, I highly suggest taking at least an hour or two to explore and relax up there. Enjoy the view!