Separating the girls
 

Can I take just one of my girls on an outing for the day?

As a general rule, it’s good for dogs to be calm and confident enough to spend some time alone, in a safe environment, without becoming anxious or destructive. However, you haven’t said anything specific about your girls — ie, their ages, histories, personalities, etc. so it’s impossible to make a recommendation about your exact situation. The best I can say is that, if your dogs are adults and aren’t used to being alone, you need to “start small” (ie, small time periods) and work your way up, paying close attention to how they react and adjusting your training accordingly.

Why do you want to take just one and not the other? Just curious.
I had a pack of 3 girls, all 3 years apart, they came everywhere with me. I never took one and left the other two home.

Separate mama times
 

Well...Abbie, 4 years old in July, is very outgoing, social and very vocal. People believe she is mean, but she just likes to bark and talk. She's a nervous wreek in the car. Painting and such. She's the one I would leave at home. Minnie Mouse, also 4 yes old, is very, social, calm and quiet.
I too have always taken them together but would like to just take Minnie for a change.

Lets start with Abbie and the car. Do you use a booster seat in the car for your babies. If not I would try that to eliminate the nervousness and panting. If they can see out of the window a booster seat may help.
I can understand just taking taking Minnie Mouse, less stress on you and more enjoyable with a quieter pup.
However, you have to work on Abbie's issue of barking when out, take her out more often, alone, without Minnie Mouse, she may need more socializing around strangers. Let her great and sniff people, take her to Pet Smart, Pet Supplies, PetCo. Put her in the carts baby seat where she is up, level, can see people. The more interaction she has with people may calm her down, not get over excited. (I never let my pup walk in any stores, he is always in the carts baby seat. I put a blanket in it to prevent him slipping through the metal bars). This would have to be a consistent thing, try it for a month twice a week or more if possible, the more times she can be around ppl the better. Then bring Minnie Mouse on these trips.
So to answer your original question, I see no harm in taking only Minnie Mouse out for the day where you both can have a peaceful, quiet day.
I don't want to lay a guilt trip on you, but, it is not something I would do.
Work on Abbie's nerviness, socialize her more, take treats with you, it can be her kibble, when she starts barking, tell her no barking, as soon as she stops quickly give her a treat. Treat must be given the instant she stops barkng, even if she stops for only a minute. She will learn no barking is a good thing because she gets a treat.
If you do not have a booster seat I suggest getting one large enough for both pups.
Keep us posted.

Everything suggests that with two dogs it is best for them to not become dependent on each other and to do lots of things with them individually. Luckily I have four so if I take one the others still have some of their pack but I do take one certain places and another certain places. I have one that absolutely hates going anywhere and it makes him very anxious so I don't force him to go anywhere but I also will not leave him without one of the others.

As Joan said, you really need to address your Abbie’s nervousness in the car as a separate issue (ie, separate from the issue of training your dogs to handle some limited “alone time.”) The most important part of working on Abbie’s car nervousness is that you have to do it slowly and gradually.

Here’s a good article on the subject:

https://www.akc.org/expert-advice/tr...-dog-ride-car/

Of course, if Abbie’s aversion to car rides is due to motion sickness, training will only go so far in solving the problem. In that case, you might still decide it’s better for her to skip “pleasure outings” that aren’t a pleasure for her. I have one dog, who is almost fifteen years old, who always gets motion sickness in the car; she rarely even makes it a full mile without getting motion sickness, even though car rides have never made her particularly nervous. So, in her case, I generally don’t take her on “fun” outings, since vomiting isn’t really fun for her, and being with a vomit covered dog isn’t fun for anyone. Her fun outings are usually limited to our own yard or walking distance.

Motion sickness
 

When I first adopted Cody he would throw up in the car, OMG. I was devastated because my girls who I raised from 8 week old pups were just about raised in cars. They went everywhere with me. When I had my girls there were no Pet Smart, PetCo, Pet Supplies in my are in NY. In Pa. where we camped there was, I once took the 3 into Pet Supplies, I needed an E collar for the youngest. All 3 went ballistic, trying to climb out of the cart. So out we went. I have to assume it was all the smells of the store, they reacted like they did at the vets office. So, I never went into one of those stores again.
Now I have a dog that gets sick in the car. The only time he was in it was for vet visits and groomer, both terrifying places for him.
Shortly after adopting him I stumbled onto Yorkie Talk and read about booster seats. I knew he needed a booster seat that was elevated off the seat so he couldn't feel the road bumps. I purchased one in Pet Supplies and prayed this would work and eliminate his sickness, (the vet did give me pills to give to him one hour before he went in to the car, I didn't want to give my dog a pill to just take a joy ride with me, also many of my outings are spontaneous so a pill wouldn't work).
That was 8 years ago. The first time I used it I had to carry him to the car, he hated the car. I put him in and buckled him up. I live on a mountain, a lot of S turns. I went down the mountain very slow, usually he would vomit before reaching the main road, well we got to the main road and he didn't get sick. I drove slower, took any turns slower. No vomit. One round trip and no car sickness.
The second time we had to go in the car he didn't fight me, in the booster he goes, down the mountain and into town. He is sitting in his booster seat like a king on his throne. He was able to see out of the window, and he was loving it. That was 8 years ago, he has never gotten car sick since, so booster seats do work for car sickness. And, when they are able to see out of the window also helps.