Since you have access to an RTN system (NTRIP), your first step can be GCP placement and it doesn’t necessarily matter if they are taken on different days. The main issue will be your baseline with the receiver from which you get the correction, which will dictate your absolute accuracy. It all depends on how accurate your project needs to be.
When you’re ready to fly your mission, set your RS2 up on a fixed point, and record the raw log, making sure you have a little bit of extra data at the beginning and end of your aerial mission. Since you know the position of your base from the RTN service, doing the 5-10 minutes average before the flight will help narrow the position down (you can enter that value as a manual coordinate entry after averaging).
When back at the office, you can post-process your aerial raw log against the fixed RS2, then you can use your GCPs to further realign the images in your photogrammetry suite.
That’s how I would do it anyway.