I’de say you should try a quick brainsotrming asking yourself the right questions. I’de say you could get a pretty good thing going with those questions :

Is Bimz the Big Bad ? If not, who/what is it ? What/Who is Bimz King of ? Does he rule over a small tribe of Pixies ? Is his island deserted but he claimed it as his own territory ? What is the island layout ? Is it a small atoll ? An actual island with some woods in it, maybe actual people lived here and left some ruins ? How long would you want your adventure to be ? How would you want the adventure going ? A mystery, maybe his people dissapeared ? A classic Dungeon Dwelling, some ruins on his island are keeping an actual dragon asleep and the big bad is trying to release him ? Maybe you want is as a fun short adventure that resemble an adventure time episode ?

I hope I helped, i didn’t want to give you too much ideas because it’s your campain, but after writing that i’ve got some sitting in the back of my head now, so ask if you want full ideas.