The NSLDS will tell you who holds the loan - contact them and make payment arrangements. I would reccomend rehabilitation over consolidation. A rehab takes longer (9 months of on-time payments + some time for the loan(s) to be picked up by a new servicer), but at the end you have a tradeline that is backdated to the original open date of the loan. It sounds like that could be a boost for your average age of accounts, and you didn't mention being in any sort of time crunch.
Once the loan is through rehab and back with a servicer, you can choose an income-driven payment plan, a standard repayment schedule, or even just make a few large payments to pay it off.
