Forget chains - use these:
<http://www.mattracks.com/html/product_information__brochure.htm>

Serious answer: put them on the FRONT tires unless you're carrying a maximum
weight in the bed and go in with 4WD.

The weight of that Cummins will be giving you all the traction that you can
handle whereas an empty/lightly-loaded bed will not supply enough weight for
the rear tires/wheels to have any meaningful amount of traction.

By putting them on the FRONT, they'll also provide more traction when
changing directions.

I second the notion to use them both on the front.  Especially for only a
quarter mile or so.

steve

If it were me I'd spring for the second set and put them on all four.

When we lived in the mountains there were several times each winter that
we needed chains to get up the last several miles. I bought quick-on
cable "chains" for all our vehicles (our Class B van and two front-wheel
drive cars).

I could put on a set on the side of the road in five minutes or less.
Although I didn't use any of them very much, I've never regretted
spending the money it required to keep a set in each vehicle all winter
long. I still carry them in each vehicle during the winter, but it's
very unlikely that we'll need them here. Might be on the road somewhere
and need them, though.

Anyway, if I'd had 4wd I'd have put on four at a time, no doubt about
it. If you're serious about what you said -- that you'll have to wait
until spring to retrieve your truck if you slide off the road -- you're
nuts to do it any other way. That's cheap insurance, IMO. If you don't
use them often, they'll last a long time. And if you do, you'll be glad
you got 'em.

You can still slide off the road with only two wheels chained --
especially if the other two are also driving the vehicle. They'll spin
on the ice and you'll be gone. I'd feel safer using 2wd if only two
wheels were chained.

FWIW, from somebody who's used chains on icy, snowy, winding mountain
roads a few times....

GB in NC