Hello! I have expirience with SIMCOM modules and GPS GSM tracker. I can make this project in Altium Designer (with 3D view). Result of work - BOM, Gerber files for manufactoring. About components: Power subsystem ST1S14 chip, LiPo charger LTC4054, Relay - HRAH-S-DC5V-C,
SIM holder -MOLEX 47388-2001 (full size SIM) or MOLEX@78727-0001 (micro SIM).
But best way - use combo holder SIM+SD - MOLEX 49448-1411
I think that size of PCB will be around 100*50 for case with placing of components on one side. If you want PCB with components placed on both sides then size will decrease.
Pls, see my portfolio.
Best regards, Marsel.