I own Fuso platform and E-350 expedition vehicles.
The diesel 4x4 2010 E-350 RB is my main daily driver and I have maybe $50k in it. We live 45 miles from the closest grocery store, so it is great for supply runs to town with the cruise control comfortably set at highway speeds. I have a massive Dometic fridge-freezer, diesel heater, a full roof of solar, etc. If I get stuck on Donner Pass in the winter I can turn on the heat, have some food, get into bed, and wait it out until the plows get everything back under control. It's a big beast, but with 4x4, 35s, and front/rear ARB lockers the only thing that holds me back on the trail is my size. If I can fit, I can get. I love having the towing capacity and storage capacity. I can either travel in it or use it to trailer one of my toys to Moab, etc.
However, an E-350 is not what I would choose for a months-long trip. That's where the Fuso reigns supreme.
The living space and creature comforts of my Fuso-based camper are hard to beat when you seriously hit the road - but it is $250,000 plus a year of labor if you DIY. Full queen size bed, real shower, 85 gallons of water, real kitchen, comfy seating, huge amounts of solar, battery storage, supply storage, and a 1000+ mile range before refueling. I won't be going fast, but who cares - this is leisure. Folks like to talk about the "rule of 2s" - no more than 2 hundred miles each day, off the road by 2 pm each day, and stop for at least 2 days before moving on. I found that 62 miles an hour was a my sweet spot reasonable cruising speed. Of course up hill and into headwinds you will go considerably slower. Remember that a Fuso is designed for in-town delivery, not the interstate.