You earn airline miles per stay, not per night. If all 6 weeks are consecutive nights, they count as one stay, so you would earn exactly the same number of airline miles for a 6 week stay as for a one night stay.

If you're going to do a long stay, you should earn points now, and convert to airline miles later. that way you earn more points the more nights you stay and the higher rate that you pay, and you get many more miles this way than by earning miles directly.

The only way to maximize miles earning directly on 6 weeks is to alternate stays between that BW hotel and some other hotel. Then you'd earn according to this chart:

http://www.bestwestern.com/rewards/e...sp?tab=airline

per stay. (But you have to stay somewhere else the next/previous night, because for earning purposes consecutive nights are considered one stay, even if you check in/check out in the middle.) To maximize this on 6 weeks, you'd have to switch hotels about 40 times back and forth, staying every night at a different place than the night before (though you could alternate, coming back to the same hotel every other night).

(This technique is called "hotel hopping". But few people do it to this degree on stays this long.)

Given all that trouble, isn't it easier to earn points on the stay, and then later, after the stay posts (if you still want), convert those points to miles?