I strongly suggest you consider Outfitter. They have been great to me since my purchase of an Apex 8 for my Toyota Tundra in 2004. I don't know what you read about negative aspects of their quality and warranty but it has not been my experience at all.
You will read suggestions on this forum to go with a bigger, heavy-duty truck. It seems you have done your homework on payload, suspension mods, etc.
There is also this article:
http://www.truckcamperadventure.com/2017/06/interview-with-outfitter-apex-8-owner-bob-hammond/You are welcome to PM me for details on my Outfitter experience.
