My dogs are princesses lol. They would be riding in the back seat lol but good tips and I like the idea of the smaller travel trailer.I have used a camper shell on a small Toyota pickup, a slide in camper on a 1-ton diesel pickup, and a Class C motorhome. All have compromises of one sort or another. The slide-in camper provided the most mobility and we could pull off anywhere and be fixing a meal in a matter of minutes. But climbing up into the sleeping area over the cab got to be too difficult for my wife. The plus side of a crew cab truck and the sleeping area in the cabover camper was that it provided places during the day to have clothing or photo gear that was immediately available.
With two dogs your best bet is a crew cab pickup pulling a hard sides popup travel trailer. The advantage of this setup is that the bed of the truck is available for the dogs while traveling. I put a heavy duty rubber bed mat in my truck which kept the dogs from sliding around. I put a fiberglass cap on the truck and then put black curtains on the windows so it would be shaded inside for the dogs and no worries about cooking them in back when parked in the sun. Travel trailers provide by far the most bang for the buck in terms of floor space and having a dry bath and plenty of holding tank capacity. Drop off the trailer on BLM dispersed camping areas or at state or federal parks and forests and then you have the pickup for transporting photo gear in the back of the crew cab and your dogs in the bed of the truck.
The problem with motorhomes is that they limit where you can go except for the small Class B type and these are fine for a place to eat and sleep but not for working or much else.
One can tow a vehicle behind a Class A or Class C motorhome but it means detaching the toad from the motorhome when making fuel stops and where you can park for groceries or to go inside a restaurant is quite limiting.