The Apple River from the Black brook Dam to Star Prairie is a fun paddle. This is 15 miles or so above the area with all the tubers by Somerset. The first Section from Black brook Dam to High bridge is full of class I to II rapids, a super fun paddle but there are 2 small water falls I portage around that can be run easily. There are constantly changing conditions with downed trees blocking the river here. Last year I cleared several spots with on an all "tree guys with chains saws" trip. But I have not done that yet this year. The end of this section is calmer with more places to fish and that continues into the next section from High bridge to Church Road. From Church Road to Star Prairie there are some more Class I rapids and you will see more people here.
Jon
PS running a chainsaw from a canoe that is floating up against a logjam is tricky and when the drinking starts it gets really crazy.   

any tips for paddling the Apple farther downstream? One river I have never paddled, tubed it many times years ago

After the drought like winter here in the Minneapolis area I was worried it wouldn't possible to get out on my favorite section of the Apple River from Black Brook dam to high bridge this year. But 6 straight days with rain have water levels way up. I caught my 1st fish (3 lb northern) of the year yesterday out of my new Old Town pack canoe. And I was able to paddle up Wappogaset creek at least mile and would have gone further but I didn't want to be out at dark by myself. This is by Amery WI and is a really wild and scenic area with good fishing. Accessible only by canoe or kayak.
Jon