It is very, very difficult to get into the camps in the south. It sounds as though you are probably a freelancer and this is going to make the next to impossible, completely impossible.
Security varies as the camps are administered by both the army and the police and some are very close to the physical border between Syria and Turkey. Most of southern Turkey is very safe and as long as you are on the right side of the wire, you are in good shape.
Antakya can be an expensive place to stay or it can be cheap. It depends on your needs. There are cheap hotels in the old market area a little to the east of the core. Street food is cheap and riding the busses around versus renting a car can reduce your cost greatly.
Really, in order to get anything done there you need to connect with some folks. Be very, very careful who you speak to as there are people who will take advantage of you. Antakya can seem like a peaceful and safe place but there are underlining tensions and there are security forces from both sides in the city. Don’t trust anyone. Don’t talk to anyone that somebody else can’t vouch for.
I would think long and hard about crossing as things are very dangerous inside Syria. It is not a very good place to ‘cut your teeth’ as they say and the situation in the north, just across the Turkish border, has been deteriorating rapidly in the past weeks.
If you wish to connect with the people you will need to get anything done, send me an email and I will provide a few numbers and names.