recording old cassette into sonar

okay, i have a 25 year old cassette of a cover band i was in once upon a time. the singer wants me to record this over to sonar.
my plan right now is to run from a cassette player into my rme ff800 with the left and right channels going to separate tracks.
i'll open a different project for each song.
once i get these songs in there are there any tricks you might suggest for cleaning these up a little?

some of mine is pretty painful as well!!

For an old cassette tape I would definitely do some extra noise reduction.  Sound Forge and Audition are pretty good if you already have those.  I recently got Izotope RX and I like it better than Sound Forge's noise reduction. 

If it sounds a little dull throw on an exciter.  CLAS from Refined Audiometrics is well respected.  Don't let the plain graphics fool you, it is good.
http://refinedaudiometrics.com/products-clas.shtml

Noise reduction
And this

Both very nice additions to Sonar. Surely not limited to just the project mentioned.

Back before I had a DAW, I did most of my recordings on a Fostex X-15 multitracking cassette.  I found that I could usually record 6 seperate tracks by first recording 4 seperate tracks and mix down to a stereo track on a second machine (lower 2 tracks) and then add on two more tracks on that tape. Over the years, the tapes started to loose a lot of top end and I had purchased an aural exciter. I was really surprised at how well this could replensh the highs without noise. Today we have the Sonic Maximizer which not only brings back the highs, but the lows as well.  It's great to have an exciter, but it really must be used properly. I also have a version of Magix Audio Cleaning Lab.  I really like the noise reduction unit in this.  You can use a sample of the noise from your recording ( Before the music begins ) to optimize the noise reduction.

Normally, I'd just create a stereo WAV track. I don't know why you'd want to create separate left and right channel tracks for something like this but choose the method you feel most comfortable with. 

I have lots of tools (not in Sonar) for this type of clean up work but I gotta tell you, one of the best bang-for-the-buck programs for cleaning up audio from tapes and records is Wave Repair

www.waverepair.com

It's like a $30 program that has some really nice features for removing hiss, pops, clicks, etc. I think it comes with a 30 day functional eval period so it costs nothing to try it out. The downside is that it's 16/44 only and it only works on stereo WAV files which isn't much of a limitation for work like this.

Your biggest hurdle, possibly, will be: will the tape play at all? Sometimes those old tapes deteriorate simply from just being. The adhesive used to hold the oxide to the binder might have leached out and causes the capstan rollers to slow down. Or the oxide has fallen off in places resulting in dropouts. Or the tape just plain breaks. Or you get print-through because the tape wasn't stored properly. Some of these problems can't be cured with software tricks. Good luck!