I have a 11 lb Bichon Frise that I've trained to go everywhere with us

. I started training her when she was a puppy & she's now 10 years old.
We can use any sort of bag/ backpack. Pick one that doesn't looks like a doggy bag. You can alter a regular backpack or large purse easily. She also lays in a baby sling (Target sells a great one for real babys that works) dressed in baby clothes.
We just make sure that her noise is poking out of a zipper. She might move her head back into the bag & go to sleep

but if you have shown her were the opening is she will move to it or use vents when she wants. Sometimes she pops her head out, but she knows she has to be quiet to get away with it- she's so quiet about it she wont even get our attention. If we catch her head out, we help her readjust in the bag (she might be uncomfortable) & pat her head. She doesn't bark or cry in the bag- you train them with treats dropped in to the bag & constant attention. In the beginning you need to constantly pat them/keep your hand on them.
Out of the bag- she's a different dog altogether. She'll bark at any person walking by or knocking on the door. In the bag, not a peep!
Always goes into Costco- stopped once exiting, employees checked my backpack for security reasons- they thought they found a shoplifter

mg: ! They were surprise but not mad, I explained that I was traveling

& didn't want to leave her in the car- she never gets out of the bag. I guess I was paying too much attention to my backpack & caught someone's attention

. She's been back many other times- only when we are traveling out of town. Target, Walmart, Drugstores, Supermarket, Restaurants.
I stay in hotels that except pets

, but I can not stay in a smoking room. I have noticed that they make pet owners stay in smoking rooms. Thus, I still have to not list my pets. I choose the hotel because it's easier to take her out for potty walks.
Yorkies & Bichon's have hair not fur that's why they don't shed & are less likely to interfere with people's asthma & allergies.
I would rather sneak my babies into a store than leave them in a car, but to each their own!