Self-installing keyless entry/cruise?

I just bought a 2004 Trailblazer LS with the basic package. To upgrade to the next LS package was $1,800, so I opted not to. I am kind of regretting it now, but the payment is already exceeding our budget, so it has to do.

My question: Is it possible to install a keyless entry system yourself with an instruction manual, or is it too complicated to even attempt? How about cruise control? As I said, I am on an extremely limited budget currently and am trying to keep costs at an absolute minimum.

Thanks.

Keyless entry isn't too hard if you already have the actuators (if you have power locks inside). If you know how to run cable and open a doorpanel you should have no problems. I've never done cruise though.