Welcome and congratulations! We too camped for years in a tent. It's hard to describe how nice the difference is moving up to a Pod. There are a lot of great things about it, but for me, having a hot shower available whenever I want one is probably the best.
There's no magic formula that I know of for whether you need a WDH. I towed for a long time without one and never had any issues. I finally got an E2 600 and personally, I just can't say I notice a whole lot of difference, but it does make me feel a little safer. I think the general consensus on the forum is probably somewhere between yes, you need it, to better safe than sorry. For weight distribution, you probably don't need a WDH with an F150 but it might be good to have anyway if you get one with integrated sway control.
Yes, you can definitely tow with the water tank full. I don't know where the tank is on a 178, but depending on its relation to the axle, full or empty can greatly affect tongue weight, which, in turn, can have a giant impact on possible sway. That can be counteracted by how you load other things in the Pod though. 30 gallons of water weighs 250 pounds, which isn't all that significant in terms of MPG when towing, unless you're cutting it close or get into a balance (tongue weight) issue.
Personally, it depends on where I'm going and how long it takes to get there. Almost all campsites have some kind of access to water, at least somewhere reasonably close by, so I hardly ever tow with a full tank. I carry 5 - 10 gallons for flushing, etc., at rest stops unless I know we'll be spending a night on the road at a Walmart or truck stop, in which case I might go with 10 - 15 gallons.
By the way, again this is a personal issue, but one of the great things about a Pod for us is the ability to spend the night at a truck stop or Walmart. It seemed a little weird at first, but we got used to it very quickly. It's free, it's quick and easy to get to from the interstate, and, since we don't even unhook, we're back on the road in minutes in the morning. That can save us an hour or two compared to finding and dealing with a campground along the way. If I have an 800 mile trip from home to my destination, that extra hour or two gets us to where we're going that much sooner!
TT
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FJ Cruiser
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