hmmm

3 gallons of homebrew. that should help with the weight issue.
you have the basic down pretty good. i could tell you exactly how i did mine, but then gpw could tell you how he did his, and then mike and patg could tell you how they did and are doing theirs. all of which will be different.
you have the basic idea, so just go with it now and make it yours.
just remember the idea as i understand it is the "sock" effect.
as gpw says, try to plan ahead. think about where you are going to cut holes in (windows/doors etc).
not much thinking went into mine, because i had no idea what i was doing and had to do it fast. camping was coming up and i had to get it done and get going.

but i did learn alot from it and i am planning a second build.
good luck to you and you HAVE to post pics. start a build thread here.
today does seem like it will be nice, as well as the next couple of days. doesn't seem to be much rain in the forecast. so i am going to go out and work on the foamie. i think i have in my head how i want to do the doors. thinking that is what i will work on first. but i need a few clamps to do what i want. and i don't have any.
..but then i think maybe i should repaint it first?
..so maybe i will just work on the inside for now?

who knows what i will end up doing.