Hello,
In terms of mobile antennas, only antenna denoted as Main antenna must be connected to the router, as it is used for signal transmission and reception. Aux connector is for a supplementary reception antenna to improve signal quality in poor coverage areas, but it is not mandatory, if you are in an area, where signal quality is good. Thus, having one external LTE antenna outside the camper should be sufficient in most cases for LTE coverage.
As for WiFI antennas, it does not matter, which connector is used for the outside antenna and which one in the camper, both channels operate in the same way.
Best regards,
