Congrats on the new rig.
No way I would let her or anyone else do this by themselves and in bad weather. It not really can she do it or will the truck/trailer be well prepared, it is the safety factor of weather and something new. If there is a problem will she be able to handle it by herself? blown tire, loose tires, bad hitch, loose axles, ice and slip offs, etc.... I always bring a buddy when picking up something new that I have no idea about. Just wait until the next opportunity and have her go with someone. No reason to put stress on her just to bring a trailer home to sit.