Long time lurker of steptalk here. 

Im 24 and have been a SM for right at 3 years. SS is 4. 
I either have a real issue, or my SO has an issue. Or maybe both of us.. 

I need serious advice. My 36 year old Step D and her 2 kids (19 and 20) just moved, without telling her dad or me, to our town 800  miles away from where she has grown up and lived her entire life. Her mom, aunts, siblings and all her friends live in her hometown of Las Vegas.  I'm so worried she has NO support system in our town (other than these 2nd cousins she barely knows) she will be expecting to be at our house all the time and I haven't spoken to her in 3 years.