We have been to Kodiak, but I do not recall any private RV parks with hookups. We visited three state parks/recreation sites with small campgrounds, but no dumps or electricity. There are dumps at a couple of places in town--see your Milepost for locations.
Ft. Abercrombie is an interesting historic site with WWII bunkers, tunnels, and coastal gun emplacements. Buskin River is just south of the town of Kodiak, and Pasagshak River is quite a way from town, but in a very popular salmon fishing area. We were there during the June king season and people fishing near the mouth of the river were hauling them in every few minutes. Not quite Kenai River combat fishing, but still very busy.
The road network in Kodiak is very limited and can easily be driven in less than a day. Personally, I would leave the RV in Homer and just take the ferry to Kodiak. Rent a car for a couple of days to see the populated portion of the island, then take a boat trip to the wildlife refuge to see the bears (you can't get to the wildlife refuge by road). After that, take the ferry back to Homer and continue your Kenai adventure. Just a suggestion!
"Retirement is the best job I ever had!"
2015 RAM 2500 4x4 crewcab 6.7L CTD; 2016 Rockwood Signature UltraLite 5th wheel