We ALWAYS travel with our boys, understanding we will be restricted in going to some places. We are prepared to put them in a kennel for short periods of time.
For us, they are BRILLIANT travellers, and go to sleep immediately. Their bladder control is better than ours and can last longer!
Being beagles, everyone at least smiles at them/us, they are a great way to meet new people, and we have NEVER been refused to go to a cafe - we always ask first and sit outside. In many cases, we have had a bowl of water brought out to us.
They are always good as bed warmers - a two dog night was named for them ;To be honest, I think it's easier travelling with the dogs than it is travelling with kids
I would, however, NEVER recommend leaving dogs alone anywhere. They could get stolen, people could tease them and stress them out, or worse, they may bite someone, or even be accused of biting someone, they can get themselves all tied up and then can't access water and shade and die from heat exhaustion.
Personal preference, but our dogs are our family members, every day with them is special, and they're around a lot less than we are on this earth. Camping is not the same without them.