The Porkies are great. As far as your itinerary, you're hitting some good spots. You might want to try to add/substitute for the Big Carp River Trail. Pretty nice views along some of it. Personally, instead of the Overlook trail to Union Spring, and then to the road, I'd take the Lost Lake Trail south from the end of the Escarpment Trail. Then the Government Peak Trail to the Correction Line Trail, and then the Big Carp Trail back to the Superior Trail head.
That time of year can be dicey. You could have 2 feet of snow, no snow, a little snow...But I can almost guarantee you that if it's not below freezing, it will be sloppy. Lots of little stream crossing with spring runoff and there aren't bridges in a lot of places either. You're gonna get wet, and the weather conditions will be a big factor.
The first picture is from the Big Carp River Trail in July, and the second photo is a typical stream you will most likely have to cross.