Not this year, I'm afraid, but I will be there again one year. Maybe 2019. I've been to two, had a fantastic time both times. Shetland and its people are well and truly under my skin and in my heart.
As to travel, there's an excellent flight service from Edinburgh to Sumburgh. I think there's also a service from Glasgow. Hiring a car from Star or Bolts they'll meet you at the airport and return you at the end.
Inter island ferries are plentiful and efficient. Many activities are in Lerwick or Hoswick, so either of those make a good base. It is useful to be able to walk around Lerwick, for sure, but even if you settled in the venue where the Hub is and didn't leave it, you'd have a wonderful week.
Getting to other venues outside of Lerwick, a car makes it easy but WoolWeekers car share, with a noticeboard in the Hub offering and seeking lifts, and also a group on Ravelry doing similar.
Oh, and the food is excellent, and wouldn't feel 'foreign' to you, Fleecewife!
. At the Mart, they have a plaque showing you where on Shetland today's food has come from, which is a great idea. Wish other Livestock Marts did it too.