This is why I think it would be best to double box items and put a unique tamper tape on the inside box so we know no one has looked inside.
If I was a source I’d put a great deal of effort into making sure usps couldn’t look at the contents without having gone through some work and then my customers would know something is up when they receive the box and could take proper action.
And no you don’t want to give your gf the box, you take the gear and you store it off your property, but don’t put anyone else at risk.
Remember cops only care about money, if you’re not a source, you don’t have fat wads of cash, own a fancy car, house, boat, lots of property they can seize then they aren’t interested in you.