Well Jim and Carmel, here is link to boondocking in AK, it is old but if you google RV Boondocking in AK you'll find a lot of info.
clickyAs far as the ferry, I don't know what great things you would see that you need to spend that much money to take the ferry. I met up with my wife and daughters in Kodiak one time and rode back to Seward with them and they went on to Valdez and then took the ferry to Whittier where I picked them up in the MoHo. They felt the Fjiordlands cruise(one day) out of Seward was better.
I would estimate the cost of campgrounds is about $35 - $45 per night in privates and less in public parks.
June, July, August and part of September, any earlier or later and you will find cold weather and possible snow.
I took a shot gun to AK the first time we drove. Didn't park the MoHo and go into the bush, so never needed it.
Just my 2 bits worth.
Dave