I would take her along to the Rv when you are preparing for a trip. Or just sit in it for a while in the afternoons... just to get her used to it.
I tried the soft sided crates, and felt that the heat built up in them quicker, I've also seen some where dogs chewed right through the sides of them. I have wire crates that fold down and can be put out of the way when not in use.
When we leave the RV, we make sure the temp is set, we crate the dogs, give them water, close the curtains, and leave the tv on. That way the dogs can't see people outside and the tv muffles outside noises. The aim is so that the dogs dont' bark.
During hot weather, we don't go far or for too long in case something would happen to the electric. The MH can heat up fast on a hot day.
Our dogs were older when we started RV'ing. I wasn't sure how they would do and I was pleasantly surprised. I told my husband, bottom line as long as they are with us, they are happy. They love going.