render from the command line. since maya isn't open there's more free RAM the Render command can utilize.

optimize the scene and delete all the history you can.

other than that, meh. i've kinda just dealt with long renders.

(if you can, see if you can render some files on other machines, too! - just don't forget to bring a .ma file so you can change it depending on the version of maya, and all the texture files you're using so you can point maya to their new location before saving the file to a .mb so you can batch from those machines... or else you'll get renders of a lot of black objects. learned that one the hard way by forgetting to reconnect files. 400 frames and a few hours down the tubes. ugh.)