You know the Rangers use some pretty specific and unique gear.
There are threads on here about it and on some of the other sites too like Arnie's Airsoft.
The unique stuff makes it a Ranger setup; grabbing up a wrong coloured law enforcement plate carrier because it could be cheap or it's easy to find isn't the best way to start your voyage.
I suggest you do a lot more searching and reading. Getting all that you need together is going to take time, money and a lot of effort if you want this to be accurate. You'll probably have to get a few interim pieces to fill in holes while the hunt is on but if you're smart about it you wont' have a setup that's more wrong than right.
Airsoft, where nothing is hurt but feelings.