The main adjectives for Rob's flat (the Bamboo Room) are compact and convenient. The former refers to the size, which requires guests to coordinate their movements around the room, but not at an unmanageable level. Much of the reason is that a large portion of the floor in the main room is occupied by a fairly spacious bed, so it's an acceptable tradeoff. There are modest supplies for making coffee and such, a fridge and microwave, but the only water for cleaning up is the bathroom sink, so there are no real options for meal preparation.
However, you're not staying here for the room or its view of the mountains, you're here for easy access to the beach. That's about three blocks away: one block to the marina and another two or so to the water. That'll put you at Kahanamoku Beach by the Hilton Lagoon Towers, which adjoins Fort Derussy beach. Waikiki is farther south, about a mile from Rob's place as the gull flies or 1.3 miles by foot according to Google. Be aware, you can't stroll from Derussy to Waikiki along the beach because of huge hotel complexes jutting over the water.
In conclusion, Rob's place provides exactly what it advertises, and we enjoyed our stay.