We take our two with us all the time. Of course, they are only 4 pounds apiece. I find that running the overhead fan and cracking a window really keeps the inside of the van comfortable for the dogs and you can leave food and water out for them. My only concern would be traveling to the beach, having to park in the sun, etc. when that's the only place to leave your dogs.
We always have our dog with us. It can be unhandy, like in really hot weather when the dog can't be left in the truck. Sometimes we just have to miss out on something. It's all good.
The only specific problem I see in your case is that some parks have breed exclusions, and dobermans are often on that list.
Some members don't look at the forum they are posting in, so you will get posts form members with Class A's, 5th Wheels, etc. Traveling with dogs in a "B" is more difficult mainly because of the heat. A "B" can heat up fast, and take a long time to cool down, so do be careful leaving them unattended. If you use the AC while you are away, ask a neighbor to check on it, (give them your cell no.) or return every hour or less to make sure it hasn't shut down. Lots of things can cause the AC to stop, shore power failure, gen-set shutting off, etc. As mentioned, many RV parks are now not accepting specific breeds, and Dobermans are on the lists.
Welcome to the forum, and happy camping.
I've run into a few problems over the years, but most were minor. Florida State Parks required up to date shots records and for awhile they were lagging the rest of the country regarding rabies shots - they said every year. A busybody in Maine called the police when she spotted our dog in the van. Windows were open and the overhead fan was on, but all of a sudden there were police around the camper. Luckily, we were on the way back and could see the potential problem and diffuse it.
There were a couple of campgrounds that asked what breed our dog was. They didn't allow "aggressive" breeds like Shepherds, Dobies, Rotties, and Pit Bulls.