time and patience.
we have 2 huskies, and they are both pretty young (2 and 3), very high energy, high prey drive etc. The younger one had some separation anxiety at first and would tear up everything he could reach when left alone. we tried crating him (at home), which was okay at first but he eventually broke the crate in any way he could to get out. so it took a little extra effort to get him to calm down.
before we started camping, we first acclimated them to the TT. We started small, like eating dinner in the TT ("driveway camping") with the dogs just hanging out. We slowly built up the length of time we would spend in there, getting them to feel like it was an extension of our home. Then we'd leave them alone for a short period, and come back and praise them if all was well. We gradually built up the time they were left alone, and it went much better than we expected. Our fear was the younger one would tear up everything he could (cushions, mattress, anything). He never did, and they got used to it pretty quickly. When camping, we have them on a tie out (most huskies can never be off leash, prey drive too high) and they bark at dogs walking by, and the occasional squirrel, but nothing excessive. if we have to leave them in the TT (we go out to dinner or something) they're fine now, with the AC on of course for the snow pups.
we do what we can to tire them out, long walks, long bike rides where they can really let it out and RUN, and this really helps as they just get too tired to cause trouble. our dogs are a big reason we got into RVing, so we can take them when we travel. IT has been great so far, and haven't regretted it one bit!