Pay in freight is generally less than passenger (although there are a couple exceptions like Fed-Ex...but they prefer high-time military US citizens).
The real issue is that you will not have the luxury to choose if you wish to fly freight or passengers....you simply will be grateful if you ever get a flying job in today's changed market. There are many pilots with thousands of hours who are currently finding it difficult to find work. They will probably have a better position in the "finding a job" queue. Anyhow, I suggest you instruct for a few years, the market will hopefully pick up around 2013/4...hopefully. Good luck...and if you need to do something else until things get better...then do it...you have to make a living and currently there are at least 1000 CVs for every 1 job opening in Aviation.