Battery dead- key inside
 

To make a long story short, someone in the family leaves their broken key (just the keychain part is broken) in the 2003 Xterra and uses the remote to get in (no spare key). They went out of town for 2 weeks and the battery died. How do we get in the car or under the hood to jump it?

Possible ideas:

-Slim jim to get in car. Can maybe fine one. Not sure about locally.
-Call locksmith- expensive
-Try to get hood open without getting inside car. Not sure if this is possible on an Xterra.
-"Jump" car (really only need power to open the door) from underneath car. Not sure how possible this is but my brother suggested hooking negative to frame and positive to big wire attached to starter for power.

I'll add that I know little about working on cars though I'm generally handy.

Thanks