I have 6 water jugs.
Four 8-gallon jugs from Walmart. I can set them on their side and they have a spigot. I leave one set up outside for washing hands and faces after riding the motorcycles and ATVs on the dusty dirt trails.
Two 7-gallon jugs from Big5. These have a short pour spout that is small enough in diameter that it just barely fits inside the filler tube of the RV. Note: holding up 7 gallons of water is a little over 56 pounds. You need at least a little bit of strength to do that. My son is 4 inches taller than I am. If he is with us then it is his job.
That is 46 gallons of extra water.
I have not used them since we replaced the TT with the MH. We used them a lot with the TT.
FWIW, when planning a trip I estimate 5 gallons of water per person per day. That allows a Navy shower every other day and a sponge bath in between. This is for 5 adults. Everyone but me drinks bottled water.
I recently bought a bladder. I have not used it yet. There a lot of campers at Quartzite that use them. They are only useful for shuttling water from a local source back to camp. I think my bladder holds 40 gallons. It fits in the back of the truck. I have not tried it in the back of the Jeep Wrangler, but I think it will fit with the rear seat removed.
Wayne in Coarsegold near Yosemite
2013 Forest River Solera 24R
2014 Jeep Wrangler Rubicon
ATV trailer for the following toys
2008 Yamaha WR250R,2009 Honda CRF150F
2008 Polaris Scrambler 500