It'll just be you and your buddy in the truck, is that right? How are you going to do the beds? My first thought would be folding beds coming down off each side Maybe do a "U" shaped counter top all the way around the sides and behind the cab. In bad weather you could cook up front and the two sides would be the beds and loungers.
I lived in Anchorage for 45 years and Alaska really isn't that cold in June, you don't need to make special plans for around cold. However, do plan on rain and being stuck inside!!! You're going at the best time but it's so variable that it could rain the whole time you were there. I moved out of Alaska in 2006 and this last summer my girlfriend and I drove back up there for the summer in her van. It was cold and snowed one time on the Alcan, but that was the only cold we ran into. It was at the highest point on the Alcan at 4200 feet and that's the only reason we got snow. However it rained a lot so we spent a lot of time inside together!
By far the prettiest places in Alaska are the Glenn Highway from Tok to Anchorage, all around Cook Inlet, and the Kenai Peninsula. Of course Denali NP is a must-see, but the weather is especially variable there and travel in it is very restricted.
The Wrangell-St Elias NP is probably the pretties thing in this country, but access to it is so difficult few people ever see it. An amazing trip is to put the truck on the ferry at Whittier (just south of Anchorage) take the ferry to Valdez, then drive back to Anchorage: FANTASTIC! If you have time and money take a boat out to the glaciers from Valdez.
The two single best experiences of my life were on this last trip:
1) Fly-in bear viewing into Halo Bay at Katmai NP. It was unbelievable how close we got to wild bears.
2) Flight-seeing over Mt Mckinley from Talketna with glacier landing. Astounding!
I blogged a lot about my trip. Go here to the "Alaska" category of my blog:
http://www.cheaprvliving.com/blog/category/alaska/
I can't help myself, I've got to put in some pictures:
Bob