You have a couple of options:
From AKV take a bus to MGM Studios and then walk or take the Friendship boats to Epcot. Boats will drop you off right at IG.
Or,
From AKV take a bus to AK or DTD and then catch a bus to BW or BC and it's a quick walk over from there.
After Merry Mixer, walk to BW or BC and catch a bus to MK for MVMCP
We'll be there on the 6th. I purposely didn't "plan" anything for that day in hopes DVC would schedule the Mixers on Thursdays, like in the past. Boy did I get very lucky. This will be our first time going to a Member party.
DH just saw the info on the Merrie Mixer on the member site, and asked me what I was planning for us on the 20th (the day we arrive, and are going to MVMCP). No sooner did he ask me, then I found this thread! We're also staying at AKV, so, thank you ChelleinNC for the options about taking the bus to MGM, then the boat to Epcot. He wants to do this (even tho' we stopped in Doorway to Dreams on Sunday and received our ornament then), so I guess I'll rearrange our schedule to add this!