We stay at Wilderness Edge every time we visit Millinocket. The campground has all of your basics and is a great gateway spot for Baxter State Park or ATV trails. 

The sites are better suited for smaller RV setups but it is not impossible to get a bigger camper in. We have a 30 foot toy hauler and have fit in our spots ok. We don't recommend coming in after dark- it can be difficult to navigate. Another thing to note is how long your hoses and electric cords are, you may need to stretch them under/behind your camper depending on site location. 

The staff here are fantastic and have helped us on multiple occasions. Our last trip we had to extend a night because our truck broke down and needed more time, it was no problem. We have also had to buy a new 30 AMP power cord after store hours because ours was making us nervous.