Well, without becoming a citizen of West Virginia, you'll have to stick with Virginia, since only West Virginia citizens can register there.
That most likely rules out the option to work as a poll monitor as well. I'm not entirely sure about West Virginia, but almost every polling place always has multiple monitors present from both the democratic and republican parties and sometimes at least one from a third party. Should any problem or question arise, it's normally required that both of them deal with it, not just one. The only exception, really, is in partisan primaries. This opportunity is limited to the citizens of each state, though.
If you'd really like to work at the polls, I'd suggest contacting your local GOP or Libertarian party office or even the College Republicans. They always have volunteers manning the polling places handing out literature, sample ballots and such. That is not restricted to state residents.
Since you'll be limited to voting in Virginia, here's a link to the absentee ballot application in .pdf format:
http://www.sbe.state.va.us/Election/AbsenteeVoting/absenteeBallotApp.pdf
Once you fill that out you can fax it to the Fairfax County Election Office at: (703) 324-3725, or mail it to them at: General Registrar, 12000 Government Center Parkway, Suite 323, Fairfax, VA 22035-0081. They will then send you a ballot to be filled out and returned. The deadline for submitting your application is October 28th. If you'll be visiting home between September 20th and the Saturday before the election, you can vote absentee in person at the county elections office in the government center or at one of these satellite locations:
Franconia Governmental Center
6121 Franconia Road, Alexandria
Mason Governmental Center
6507 Columbia Pike, Annandale
McLean Governmental Center
1437 Balls Hill Road, McLean
Mount Vernon Governmental Center
2511 Parkers Lane, Alexandria
North County Governmental Center
12000 Bowman Towne Drive, Reston
Sully District Governmental Center
4900 Stonecoft Boulevard, Chantilly
West Springfield Governmental Center
6140 Rolling Road, Springfield
Good luck!