You will find this elsewhere on the board, I'm sure, but it's worth repeating: if you need activity in your account in a hurry, one of the fastest ways I know to accomplish that with minimal expenditure is points.com. Just exchange (not trade) enough miles out of another loyalty program to get one mile in AA. (You can also exchange miles out of AA into the other program.) The transaction typically posts in no more than 24 hours, often less.

As any activity will reset the clock on your account, this will do the trick. Just be aware that the points.com exchange rate is terrible, so this is not something you want to do in large quantities, but for keeping an account alive it serves a purpose. It will cost you around 5 miles out for every mile in.