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I'm guessing the majority of new RVers, especially new full timers, end up with either larger or heavier RVs after they have been on the road for a year or more. If it was me I would stay away from purchasing a half ton pickup even if it was rated to pull a fully loaded Hideout 34 model. If you decide in a year or so you want a 5th wheel for example that half ton will have to go.
Looks like the model you are considering has a place for a washer/dryer. A few things to consider when you start to match up your TV (tow vehicle) to what you will be towing. On our first full timing RV (used fiver) we added a washer/dryer and a automatic satellite dish on the roof, then after loading all of our personal property we ran across the CAT scales. We added over 3,000 pounds to the fiver. At the end of the first year we weighed again and had added another couple hundred pounds. So my point here is if that unit you are looking at weighs a little over 8,000 pounds you will probably need a TV that can tow at least 12,000 pounds.
Gas or diesel? Initial cost on a diesel will be much more of course. As far as operating expenses there are a lot of variables. Annual maintenance may be slightly higher with a diesel pickup, but you may get better mpg. You certainly will have more torque and towing ability. The price of diesel fuel has been higher in recent years than gas, but there are ways to get discounted diesel. A Pilot/Flying J card (Good Sams) will get you a 9 cents per gallon off at their stations. There is also a discount fuel card (EFS) that we use and depending on the truck stop we have received as much as 60 cents per gallon discount.
Besides deciding on a TV and RV, have you considered becoming residents of another State as full timers or are you sticking with your home state?