Rainforest Trekking Near Vanimo or Sepik River

I'm hoping to cross into Jayapura at the end of May to Vanimo and either do 5 days of rainforest trekking somewhere near Vanimo or in the upper Sepik River basin. I have a total of one week to spare in PNG. Can anyone recommend a place for rainforest trekking in these areas. I plan to hire a local guide.

Thanks,