The Tekkeon on its own can power the Nokia for 9.5-12 hours.
And for 25 pounds while camping, I have a small 8.8 pound 12v geny I picked up in Japan a few years ago. It is made by Robin (Subaru) it is nifty. In 12v2A mode it runs for about 3 hours on 20oz of gas. It will carge my 15.4" gateway laptop only if it is off. but will power it if the batt if already charged. But for 10,000 yen (98 bucks at the time) it was a good buy. Down side is some parks do not allow it during dry conditions. It is sorta quite...ish. From what I can tell it is a large hobby airplane motor. I forget the displacement but the gen motors them self are 2 full "can" RC car motors, I know this since one died I put a Tamiya 550 in it and it works fine.