A gem of a place on the mouth of Wailua River. Fern Grotto Inn is a bespoke kind of place with just a handful of units, where each unit is unique. Photos don't do justice to Coco C where we stayed -- it's MUCH roomier (comfortably accommodates a couple) and has a new house feel, with brand new appliances, a huge bathroom and modern kitchennette. Internet was fast.
The grounds feel magical and secluded - there is little settlement immediately nearby and you can peacefully enjoy the company of chicken, lizards, geckos, birds and other local denizens. There are kayaks and you get direct access to Wailua River where you can further enjoy the immense beauty of the surroundings. There are even bikes and helmets and you can enjoy the local trails along the coast. Park is a cinch - you leave the car next to your unit.
The location is strategic - the river is right there, the ocean is 3 minutes' walk away (although for safer swimming you're advised to go to a beach that's 10-15 min walk away), downtown Kapaa and shopping is 3-5 minutes' drive and the Lihue airport around 10 min. The Kapaa/Lihue area is convenient for exploring the rest of the island - you can reach most of the North and South in well under an hour.
The host, Paul, deserves a special mention. Truly outstanding and really takes care of his guests. Paul makes you feel at home - both with his thorough furnishing and equipping of units with everything you need (from various utensils and we even found complementary chocolates and condiments), to letting you use bicycles, kayaks, laundry facilities, etc. You really feel welcomed and I wanted to say thank you again. It's an excellent place and we'd love to come back one day!