How to admin my NR2301 mobile router on the move

I bought my NR2301 router to be able to have a broadband in my camper van or RV. It means that I have to be able to admin my router if its battery runs empty or I have to restart the router. If it needs to be restarted, I have to be able to access the admin pages to enter the SIM cards PIN code to make the router work again. This seems to be impossible with a phone or tablet. I have to use a laptop of any kind, otherwise the ip address: http://192.168.1.1 to the NR2301s admin page can't be reached or loaded. I have tested this for some time now, and the only the time the admin page can be loaded, is when I have unlocked the NR2301 SIM card with a browser on a laptop. No Zyxel Air app handles this challenge either. This is not convenient when I prefer to only have mobile devices with me on my RV trips.