We stayed at Ulonga Lodge as part of a short tour 'round South Australia. We took the ferry from Cape Jervis. The crossing was about 45 mins and only a little rough. KI is fab. We were out of season and so everywhere was really quiet. The Flinders National Park had a few walks closed due to bushfire damage, but was still worth a visit.
The lodge was basic, but spotlessly clean. Everything worked and we had a friendly welcome by Cath and Steve. Cath's daughter even lent me her fishing rod for an hours fishing from the jetty.
Kangaroo Island Lodge next door has a nice restaurant and a bar (bar for locals really).
KI itself is so beautiful and unspoilt - an ideal break from the bright lights.