Maguk is an easy-moderate walk with some small water pools on the way. When you arrive, it is a large waterfall in a large rockpool. Generally pretty empty too, no clue why as it one of the best spots in Kakadu.
On the temperate scale of Kakadu water, it is probably the warmest place you can swim. Big crowds are rare for some reason.
There is a camp site which I haven’t stayed at, alcohol isn’t allowed.
There is also some rock pools above the waterfall. There are signs everywhere saying you aren’t supposed to go up there, yet I see guided tour groups using those trails regularly, so I don’t really know the answer.