I'm using the most recent trainer.
Total War Rome 2 Emperor Edition V2.4.0 Trainer +15 Build 19683
With all the radious mod packs from steam. I usually start the trainer, then the game, and activate the trainer in the main menu before doing anything else. I also reset all the hotkeys in the trainer before using the trainer (it comes pre-set, but it was one of the things i did in the process of getting it working). No crashes so far. I remember this game used to crash all the time, and I recently reinstalled it. If the problem continues maybe verify the files through steam, or just completely delete it and reinstall.