X5 on the Dalton Highway in March - am I nuts?

[teffi71]

Folks -

it seems that in March I might have some free time on my hands and so I am planning to drive from San Jose, CA all the way up to Prudhoe Bay, Alaska.

Did anybody drive up there already with an X5?
If so, what was your setup?

I have a 2008 BMW X5 4.8i w/ sport package (original w/ 20" - now 19").

What do you recommend to make my ride safe(r)?

* Winter tires (as 255/55R18 109H XL):
- Dunlop Grandtrek SJ6, or
- Toyo Open Country A/T II
- others ???
- I am thinking to have a set of 6 tires on rims (=2 spare ones)
* Snow chains:
1 pair or 2 pairs? The user manual says to put chains only on the rear axle
* Engine block heater?
* Underride protection / skid plate?
it seems that the BMW original one is no longer available.
Do you know about custom made ones? Who?
* Which spare parts should I take with me in case of a break down?
* Will my extended warranty and maintenance be valid in Alaska?
There seems to be just one dealer in Anchorage. Will they honor it? What about the Canadian dealers?

Any infos / ideas are highly appreciated!

Thanks!