I am generally in, due to what cookie says about the free reign of Tories with no boundaries. However, the thought of Turkey joining the eu then having complete freedom of movement does concern me. That said, there is no chance of Britain being able to sway things they aren't inn the eu, so...
Turkey aren't joining the EU. There's literally no possibility of that happening; Turkey haven't even formally applied, and it would take many years (decades) for Turkey to be fully treaty compliant, and their membership application could be easily vetoed.
The Leave side are talking complete shit about Turkey and Ukraine joining the EU, basically. Those countries have tried to get association agreements with the EU for trade liberalisation reasons, and nothing else.