FMC 737 is fully compatible with routes created in the 767/757, you can use routes created by 57 67 in the 737.
FMC 37/57/67 also supports importing airways from Prepar3D/FSX flight plan.

In this short 3 min video showed how to create a flight simulator flight plan, import it into the 737 FMC with the airways, add SID and STAR, and save it in the native Captain Sim route format (saved file EGKKEIDW.rt is located in p3dv4\Captain_Sim\737-classic\routes).
Sorry, no mouse pointer on video.

This video also shows that there are no problems with DEP/ARR, or I do not know how to see it.