Bathing regularly is highly overrated. When on the road I bathe very little, going many days or even weeks.
I have this debate with people in car life forums every so often, even had someone respond to a 6 year old Reddit thread the other day. With the usual sass, showing their total ignorance of how human sweat glands actually work. I try to tell people, but much like global warming, you have to actually be interested in the science and go look up the stuff yourself.
We basically have 2 different kinds of sweat. Only 1 is the smelly kind. Has something to do with stress release. If you can avoid producing the stinky kind of sweat, you can go a very long time without any need to bathe. Like maybe douse your private parts in a sink in a one room bathroom somewhere, but that's about it.
Also, avoid manual labor. I mean if you're hauling dirt, doing construction work, or my bane sometimes is sawdust from woodworking, yes of course you're gonna get stinky from that stuff. If you're not doing that though, you're not.
Don't track a bunch of dirt into your car. Shoes "outside". I restrict my shoes to my driver's footwell, so that I'm lessening the amount of dirt and sand I'm taking in.
My worst hazard wasn't my own lack of bathing. It was really my dog, when he was alive. I miss him.
Over the years, I discovered that cardboard food packaging and grocery store paper bags, are extremely useful for cleaning dishes. They absorb grease and are a great "first go" at the dishes, to remove gunk and conserve scarce water supplies. Better not to keep paying for dish soap too, or avoid it entirely, depending on what kind of stuff you cook.
Well those paper products work on your body too! If I am going to bathe, that's my preferred method now. They're basically disposable washcloths. One room bathroom drill again somewhere. Doesn't take that long because again, you're not anywhere near as filthy as society tries to have you believe.
Just realize you've been brainwashed all your life by the petrochemical companies trying to sell you more stuff to put on your skin and hair. That's what it's been about. Money. Big budget marketing campaigns to make you feel like a lousy human being if you're not doing what the supermodels on TV are doing.
BTW the only soap and shampoo I like is Dawn. Yep, Dawn. Even if I'm in civilization and have a full shower available, I use Dawn. 'Cuz it's good enough to take even automotive grease off my hands and body, without making my skin feel like crap for doing it. Works for ducks in oil slicks (original formula at least), works for me (the actual stuff sold at retail nowadays).
Also note: changing clothes has some of the value of bathing. It removes oils and dirt from your skin. I wear clothes until they start feeling "icky". Lately I put the dirty clothes in plastic grocery bags, tied shut, until I'm ready to wash them. I often hand wash my clothes in a sink somewhere, something I had to learn how to do when surviving with my dog in his old age. 1 or 2 items for most things is not a big deal, and I hang them up to dry on paracords inside my car.
Hand washing jeans though is a PITA, because they hold so much water and take so long to dry. I try to avoid doing that by hand. All the thinner stuff though, it works fine.