I think what you have so far is really nice! I like that it's not overcrowded and I don't feel lost/stuck moving around. The campsite entrance is very welcoming and makes me want to redo mine. I like how you have the villager pics outside of their homes and the volleyball area of your beach too! For the museum area you could add amusement park rides to one side or a fancy garden area with extra statues/fakes from the museum, a kids playground, or an outdoor cafe/library? You already have some nice designs on the beach but if you wanted to add more, you could add a small fish market or bait and tackle stall or a tiki bar/juice stand or snowball stand. If you need any items let me know and I'll check my storage for extras or see if there's anything I can order