Since posting my planned power system, there have been several important updates and discoveries.
I won't repeat the previous planned power system, you can check out that post here if you want to read about it. Since posting, Bluetti Power released their Apex 300 power station. This is a massive improvement over previous portable power stations, with the possibility for integrated MPPT solar charging, DC power expansion, and more - for a fraction of the price of other stations.
What does this mean for the van?
The van will have a hybrid power setup. All AC/120v power will run through the Apex 300. All devices that use a traditional wall outlet will plug into this device, or potentially extension cables running to outlets throughout the van. For DC power - the station will use the D1 expansion module, which allows DC power output to a DC fuse panel, which will power all lighting, the fridge (which I haven't posted about just yet), the Maxxfan, and several 12v USB-C ports throughout the van for phone/laptop charging. The power station allows AC/Inverter shutoff to save power when you're not using any AC outlets.
This is a major change from the previously planned power system with a dedicated 3000w inverter and all of the cabling required. All DC components will still be hardwired, but AC won't have to be.
What about the capacity?
The power station has an inverter output of 3,500 watts (roughly), and allows shore power, as well as solar input. The base power station is 2.8k watt hours, with expansion modules available at 2.7k watt hours each. Initially, I'll buy the station and 1 expansion, with future expansion up to 4 modules for a total of ~14k watt hours (the bank supports up to 6 expansions (19.5k wh), but this would take up a lot of space, be extremely heavy, and very expensive).
An important note: The actual power consumption will always remain around the same amount, the total power capacity is what I'll be looking to expand in the future. This only helps in situations with lower/no solar input, or longer periods without shore power. To give you an idea, with my expected power usage, a 5.5k watt hour setup (which will be the initial) will run around a day and a half without solar or any charge. It can run around 3 days with expected solar input. For the ~14k setup, those numbers are over double. In reality, I'll have shore power at least twice a week to fully recharge the battery. Additional accessories can be added later to expand solar input for portable solar panels.
The Cost
The Apex 300 is very reasonable priced for the punch it packs. It's priced at $1,300, with expansion modules listed at the same price. Building a 900ah power system would cost around $6,000 on a traditional battery+inverter setup. This setup with around the same capacity will sit at around $5,500 - with the ability to work up to that amount (starting at the base price of $1,300 + $400 (D1 module), and expand additional options later.