I would actually advise avoiding a paper tech in this situation. My bet is that the "director" will fill your script with five hundred pipe-dream cues during a paper tech meeting that will last forever. Then they'll all change anyway when the limitations of the dimmer rack and sound system, and the clock running out on tech time, force you to five or six cues total. Your time is better spent in reading the script four or five times to get familiar with what they're trying to do, and being ready to throw it all out the window and start from scratch when tech starts. Like mc said, quick and dirty notes, no prep work.
Since they're adding you just for tech and perfs, they obviously don't need creative input for you. Be real clear about your boundaries. Give the time that you can give, and make sure that the time you are there you're making the show the best it can possibly be. Don't let yourself be corralled into being a production manager as well as a stage manager, just concentrate on making the show you have work as well as it can.