new rv life

I’m planning to buy an RV because I’m tired of paying rent, and I've decided to go with a 1994 Holiday Rambler 36LE, which has a 50-amp electrical system. I live in a town with a population of around 21,000 people, and my girlfriend lives about 20 minutes away in a nearby town. My plan is to primarily park in places like Walmart or Home Depot parking lots, or anywhere else locally where I won’t face issues.

Since I’m unsure how long the RV’s power will last once fully charged, I’m also planning to purchase a Solix F3800 power station to supplement my energy needs. Once the power station is drained, I intend to drive to my girlfriend’s house to recharge it. Solix informed me that it takes about 2 hours to fully recharge the F3800.

What I’m trying to figure out is how long the F3800’s 3.8 kWh capacity will last before it runs out and needs recharging. Specifically, could I potentially get up to a week of usage before needing to recharge from her house again?