All of Qantas's 717's have been routed through Anchorage Alaska.
Seen them all except for VH-VQK so far. Look back announce them in various posts here.
I doubt they have extra tanks installed Probably going Anchorage to Russia then Japan and down south.
I also remember seeing a bunch of Impulse Air's 717's going down there two when they where still around, That was about two years ago.
And when I worked out in Cold Bay we got some of Cebu Pacifics DC-9's that they got off Air Canada. Didn't have any tank modifications.
Since these aircraft are not carrying passengers you can usually top out the tanks. The only time you would need the extra tanks is in the case of a very long overwater segement, such as west coast, Hawaii.
Even then when I was working in Cold Bay Alaska we got Air Force C-9's that where on their way down to Hickam. I don't know if they have any extra tankage in the bag compartments but there was not any upstairs.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.