Here's a quick back-of-the-envelope calculation. Choose your own numbers if you don't like mine. What's the most solar you can reasonably fit on the truck or as portable panels? A few hundred watts? Certainly less than 1kW. You're not going to get the full output at all times of the day or all times of the year. Figure 5kWh/day on average, best case. (That's 10 miles of range a day, assuming 1kW of solar panels). The battery capacity of the large pack is 135kWh. That means it might take on average 4 weeks to fill up that battery using only the solar on the truck. And you won't be charging overnight as you sleep - you need to be parked in the sun during the day, not traveling. And finally, what is the cost of that solar? I think you will find that spending thousands of dollars really isn't worth it for just a few miles of range per day. If all you're doing is commuting a short distance to work and parking outside in the sun then it might be convenient to have and you might think it's worth the cost. Or if you're simply using it to power your camp kitchen and refrigerator while on an extended boondock to keep from running down your battery, then it might be worth it.
For me, I am rarely in one spot for more than a night or two at a time, so I personally don't think it's worth it.