This lake is in the Palms Book State Park in Manistique, Michigan.  It is the "Big Spring" in the area, and filters clear water into the lake.  There is a raft you can go out on and take turns on the wheel to move it back and forth across the lake.  While you are on the raft, there is an open viewing area in the middle of the raft, which allows you to look straight down into the spring.  You can see the water coming into the lake from the spring, and the large fish swimming in the area.  It is a stunning experience in a beautiful setting.  There are also bathrooms, concessions, and ice cream sold here.  There was an entry fee of $11 for out-of-state vehicles, and I believe $8 for in-state vehicles.  We had a nice picnic here and the kids played on the swings.  

Address: M-149 (a mile north of Co Rd 455 junction)
                  Manistique, MI 49854

One of our favorite things we did to fill time was go to Horseshoe Falls in Munising, Michigan.  There is a fee of $10/adult and $7/child to use the grounds here.  In my opinion, it is completely worth it.  There is a gnome scavenger hunt here that our kids were completely obsessed with.  Did I mention each kid gets their own gnome hat to keep - it was just too cute!  Each gnome has a unique name, and there are A LOT of gnomes for you to find.  You also get bonus points for fairy doors and horseshoes you find.  There is also a trout pond where you can feed the trout.  When we were done with the gnome hunt, we walked the short distance up to a stunning waterfall they have on the property.  It felt like we were in a fairy garden or forest, it was such a beautiful setting.  This place has plenty of space for kids to run, play, and explore.  They also have a gift shop and ice cream available.  At the end of the scavenger hunt, kids check back in and get to pick a prize from the treasure chest.  
Address: 602 Bell Avenue
Munising, MI 49862

​We took a two hour cruise through Pictured Rock Cruises.  There are many options available, however we felt this one fit our needs with younger kids.  They also have longer cruises and sunset cruises available.  It costs between $44-$52 dollars, $14 dollars for kids 4-12, and $1 for kids 3 and under. We really enjoyed this tour, it was just long enough for young kids.  The tour guide had great narration to go along with the history and landscape.  We spent a good deal of time on the back of the boat, where you can stand if you want.  There are three levels to the boat, so arrive early if you want to be on the top deck.  
If I was with a group of adults, I would definitely look into kayak tours available.  I would use the Pictured Rocks Kayaking company.  The boat goes with you while you paddle, and then loads and unloads the kayaks from the boat so you can see more of Pictured Rocks without extra paddling.  Tours cost between $99-$168 depending on what kayaking route you want.  
Address: 100 City Park Drive
                  Munising, MI 49862

After the tour, we got lunch in Munising, then headed to the beach.  We were looking for some place for our kids to safely swim, and we found THE place!  Miners Beach was a dream for our kids, and it gave me peace of mind letting them swim here.  There was a small river flowing into Lake Superior here, which almost created a backwater area that was shallow and clear.  The kids almost had a tidepool to play at here on the beach, with warmer water than Lake Superior.  They spent time splashing in the waves, then heading over to the shallow, warm water by the river.  We spent hours here before we headed back to our rental for dinner.  You should know there is a short five minute walk to get to the beach, and it is down some stairs, so you need to be able to carry anything you take or have multiple hands to help get wagons down to the beach.  
​Address: H58 Miner Road
                 Shingleton, MI 49862

There are so many beautiful waterfalls and waterfall hikes along the Lake Superior shore.  When we went, the water was low, but I am sure during spring these waterfalls are mesmerizing.  We saw a couple of the falls on our Pictured Rocks Cruise - Spray Falls and Cathedral Falls.  The next day, we spent the morning hiking and chasing waterfalls.  We went from west to east on the waterfall tour because of where our lodging was.  Our list is below.  
Alger Falls
Wagner Falls
Munising Falls
Miners Falls
Elliot Falls
(Sable Falls was too far for our kids)