if you want to sync up the video with the audio, you will definitely need a time-code generator. If you have a V3, there is an output you can use.
For multitracking, you will need to have a way to split the snake from the main snake>monitors>board>you. Plus, you will need a mixer to hook your end of the mixer up to the snake. From the mixer>your mulitrack recorder.
You dont have to do a lot with the mixer since all the EQing and level adjustments will be finalized in post-recording production. The Mixer is just so that all the levels from the snake are coming in properly.
For recording the multitrack audio, use the tascam DA-38/88. The great thing about multitracking is that once you set the levels to all be equal when you go back and master that tape, you can adjust the levels laters. Multitrack recording is quite easy to do, its the mastering process that takes time to get it perfect.
Even if you have a laptop, you will need to make sure it can handle multiple inputs. You will need software and hardware to handle the load.
If you dont have access to all this, try to get in early, and see if you can use the AUX sends from the master board. It will only be a stereo recording, but it should sound good. Since you can adjust the levels of each channel without affecting the main mix it is similar to the post-production mixing of the multitrack tapes, only you have 1 shot to get it right
Good luck! It's a lot of fun to setup a multitracking station and then once you have the levels set, there isnt too much else to worry about.