With a dog you don't want to go too small. We travel with 2 cats and just traded our 35ft class A for a new SUNSEEKER GTS 2800QS. This is 30' class C without the overhead bed. It has 4 slides which really makes a big difference in room when set up. We don't tow a car and don't want to. It drives so much better than the class A even to the point of being able to drive with one hand on the wheel with trucks passing and 30mph crosswinds. We looked at smaller units with the corner bed but trying to make up the bed was not going to be easy. So far this unit fits wherever we want to go.
