We had a great honeymoon at Tony's room at the Kauai Beach Resort. NOTE that this is not a typical AirBnB but basically a hotel room booked through AirBnB (as is listed, but still odd I think). The hotel staff treated us no differently than any other guests and the resort itself is very nice.
If you want to spend a lot of time on the north shore, it is a bit of a hike, but we enjoyed being able to split our time between North and South shores more easily (plus it's very close to the airport, making arriving and leaving very easy). If staying here and wishing to see the island, I think that renting a car is an absolute must.
SIDE NOTE: We received a scam call late at night (around 11 PM) one of the evenings from a man falsely claiming to be a hotel manager, asking for credit card information. We did not provide any (as one never should) and confirmed with the hotel staff the following day that this is not altogether uncommon. BEWARE OF SCAMS!