I used to keep my cat's water bowl in the bath tub because he loved to play in the water and tip it over. Once I got water fountains this behavior stopped. I also got a travel bowl with velcro on the bottom and place those on a rug (that's secured by table legs) and my little guy was unable to get that flipped, though your girl might be more determined, ha! Here's the link to that bowl: https://www.amazon.com/Road-Refresher-Slobber-Eliminates-Messiest/dp/B07NQ3W7CF/ref=sr_1_5?crid=2B5IRX4ZG1EKI&keywords=travel%2Bbowl%2Bno%2Bspill&qid=1646577509&s=pet-supplies&sprefix=travel%2Bbowl%2Bno%2Bspill%2Cpets%2C231&sr=...
Most importantly
"What do I do about food and water" Food: Bulk! Get yourself a good sealing plastic container, most can hold about 50lbs dog food. If you can't get that I used to keep 3 bags on the truck at a time when over the road. I only do 1 bag now that I'm home weekly.
Food bowl: Get a good steel bowl, easier to clean. Buy some sticky Velcro you can attach to floor and bowl so it will stay in place if you find yourself moving and the dog(s) aren't finished eating. It'll also help prevent them stepping on it and launching food all up the front of the truck
Water: I usually buy 2 1 gallon jugs of drinking water and carry it on the truck. I've found this is the best way to avoid stomach upset. Some tap water from truck stops can set off the pups with sensitive stomachs. When I did OTR I would carry one of the big 5 gallon jugs I'd refill about once every month at a Walmart. You could also just use cases of water but that's a lot of plastic, space, and effort.
Water bowl: I use Prestige Pets Road Refresher https://www.amazon.com/dp/B07NQ3W7CF/ref=cm_sw_r_apan_glt_i_EKVYJBZGVM2EBPNAYYWH Cuts down majorly on him taking water all over the truck and I can keep fresh water down for him while driving. You will need to clean this about once or twice a week as plastic based bowls get slimy real fast.
No idea if this would help but maybe you could try a travel water bowl? I have one that has a perforated layer that floats on top of the water and thereby limits how much water is out and how quickly the dog can drink. Like this: https://amazon.com/Road-Refresher-Slobber-Eliminates-Messiest/dp/B07NQ3W7CF
Best spill proof bowl I’ve owned: Road Refresher Prestige Pets, The No-Spill Slobber Stopper Water Bowl for Dogs, Slow Feeder Water Dispenser Bowl for Home and Travel, No More Messy Splashes, Spills or Drips Ideal for All Breeds https://www.amazon.ca/dp/B07NQ3W7CF/ref=cm_sw_r_cp_api_glt_i_JJGD6B8H6DMJ4E2PRWY2
I have the small plastic ones along with this one. My smaller dog and cats love the square ones, but the bigger dog with the longer nose needs the depth of the larger plastic bowl. (She'd probably do great with the slopper stopper too, but $20 was cheaper than $55.)
Just get this
Road Refresher No Slobber, No Spill Dog Water Bowl | Eliminates Water Slobber from Even The Messiest Jowls, No More Wet Floors | Ideal for Home, Trave https://www.amazon.com/dp/B07NQ3W7CF/ref=cm_sw_r_cp_apip_1ybzjP8Z4Milx
I have 2 huskies I take with me on a 15ft. I recently got some platforms (https://railblazausa.com/product/railblaza-fish-finder-mount-r-lock-s/) to mount a no spill water bowl (https://www.amazon.com/dp/B07NQ3W7CF) its made it a bit more comfy for them, I also throw a couple dog beds in there for comfort. I just ordered a canopy so we can dodge some of the intense florida heat (https://www.adkcanopy.com/shop/canoe-canopy)
My GSD mix is the same way, I found this Road Refresher bowl to be great in reducing the mess. It doesn't totally solve the issue, but it certainly helps. I had an unused oil pan tray so I placed that under the bowl to help contain any water drips/puddles. I was tempted to buy this big water trough-type thing, but my dog would just try to "swim" in it lol, but it might work for you.
I also agree with others that keeping plenty of fresh water available throughout the day will help as well. I think part of my dog's water gulping stems from his early life as a stray puppy, where water was a limited resource.
Good luck!
Here's the link to the amazon page!
https://www.amazon.com/Road-Refresher-Slobber-Eliminates-Messiest/dp/B07NQ3W7CF
Kind of a pain to clean but does it's job amazingly. I have wood floors and it keeps them bone dry.