Don't take it to apple yet!! Since you seem to have been able to open up the machine, you can check if the logic board is working or not. There is a chance it could simply be your keyboard and power button are fried since there wasn't much liquid. Apple will charge you a $755 flat fee to diagnose and fix the issue, when you can diagnose it yourself and maybe fix it if you know someone handy.
If you take off the bottom of the laptop and take a look at the logic board, you'll see two larger "silver pads" that are usually directly above the keyboard connector which is near the bottom left of the board (if the battery is oriented to your bottom right) You first want to disconnect the keyboard cable by lifting the small latch up and gently pulling it out.
Then, If you use a fork or something similar to short one or both of these "silver pads" (which involves simply touching them, for me I only had to short one) and your logic board is intact, the machine will turn on. it is quite an interesting phenomenon. This is actually the last step in the official apple tech manual, except instead of replacing the entire topcase...
If trackpad works, you now know that you simply need a replacement keyboard, which is actually part of the power button! a $50 part. Don't leave the machine on with that keyboard in there though because the residue could be transferred around the computer and damage other areas.
this is a picture of the power pads on my logic board, it probably is mostly identical on yours. They are the two larger silver pads underneath the chip on the left/top/center.
I'm thinking about adding a keyboard replacement guide to this site soon, since I literally had the same issue as you and am waiting for my replacement keyboard now. But honestly it is not as difficult as it may sound. The only tricky things I've had to deal with so far were taking off the camera ribbon cable and the display data cable. I will report on how difficult the rest of the process is.