I know it can't be helped but I would go spare not being able to tinker with my rig if I had to have it in storage.......
With wheels and tyres not all are the same for the same model but you can browse the catalogues at least, I would go for a LT tyre with a mild AT pattern, oyu don't need an aggressive chunky tyre on a van, any alignment issues will chew them out quickly and the only thing going for the chunky off road tyre is the look it certainly has no road holding capability as a lazy tyre, even on dirt roads..... I wouldn't use he cheap chinese stuff, in a van you want a tyre that will go the distance in time not so much in Kms so a known brand, an "LT "tyre doesn't just give you an extra ply or 2 but compared to a "P" rate tyre it means you aren't inflating to near max pressure, I run LTs on the tug as well ................ with your new tyres experiment with what pressure they like to run at, the tyre placard is really just a starting point, different brands/sizes/styles require a different pressure..........
I enjoy tyre shopping but am astounded at what some pay for a tyre so they can have some cool lettering.........