We went from owning a home and years of recreational boating, and no RVing, to full timing.
A year prior I did a ton of research and purchased my TV. The hard part during this decision process was picking between a dually and SRW. There was never any question the truck had to be at least a one ton.
By going with a F350 SRW we limited ourselves in FW lengths. This last year we have been slightly over on our weights which drove me crazy. As a full timer putting on a lot of tow miles every year I always thought you should try to stay within all your weight limitations/specification for your truck.
We just went though our fiver and got rid of about everything we hadn't used recently. It was amazing how much stuff we were hauling around and not using. Several heavy pots/pans that hadn't been used in over a year.....the list goes on and on, but all those small items add up. We will be hitting the scales soon and I am hoping to be where I need to be.
The short version is if, as full timers, you don't want to limit your present or future towing capacity then get a 1-ton dually. Just keep in mind that you will have to get used to some tight parking issues when using it as your daily transportation.