Boondocking mode:
If you don't want to carry water all the way there, fill up your freshwater tank at your last overnight stop the morning you leave. Or at a local gas station you can fit through (use google maps satellite view to see if can fit). Call ahead to be sure they allow filling up.
After filling, driving down the road, when you turn corners look in your mirror for water sloshing out your freshwater tank vent. Some have reported loosing 1/3 of their freshwater going down the road, especially on interstate clover leaf (centrifugal force). Maybe put a plug in your freshwater tank vent. Dont forget to remove it when you get there or you will collapse your freshwater tank.
For boondocking, we put Rubbermade (6 quart small sink) and Sterlyte (16 quart large sink) tubs in our kitchen sinks. Wash in one, rinse in the other. Wash water becomes flush water. Rinse water becomes Wash water.
Or use paper cups and plates and use them for fire starters. Be aware of regional fire hazard areas.
Don't run the water when brushing teeth. Fill a cup of water and only use that, one per person.
Navy showers: wet down, turn off water. Soap up. Rinse off.
Marine shower. Wet a wash cloth. Wash, rinse. Or go swimming ��.
Use the facilities as much as possible.
Last summer we went 2 weeks without dumping while dry camping. I did use the water bladder to refill us.
Water bladder
We bought an EZ pack 25 gallon water bladder. Water is heavy. This one is 200lbs when full. Depending on your rig you can gravity fill or get a water pump (like in your rig, good for a spare) or use your Winterizing mode (depends on your rig) to transfer the water. We like this one because you can replace the internal bladder when you need to.
EZPACK Water Storage Bladder - Water Container with Spigot - BPA Free Replaceable Bag - Water Tank for Camping Gear Essentials, Road Trip Essentials, Hurricane Supplies for Home
https://a.co/d/63FUmap