I am really close to my family too, and I'm sure you will miss them, but what an amazing opportunity.
FI and I are taking an RV trip to California this winter and going with the "seat of our pants" mentality...which is hard for me, but we have done it once before and it was the best 2 months of my life!
We have also talked about moving away and I have had the same fears, but I know I would regret not doing it...I want to have stories worth telling!