About to return to truck campers - but need help

restlessways wrote:
Have you by chance checked the difference in registration fees between a 3500, 4500 and 5500? I've always wondered if there's a difference. And what about insurance?

It is not just the registration fees.
In CA you pay for declared GCWV, so you have to estimate max on your trailer as well.
But crucial number for GVW is 15k lb, who in CA falls under smog law, who require engine replacement after 10 or 15 years.
Nobody wants that.