You truly don't need any curriculum for pre-k. However, since you asked, we liked this for math skills: http://www.singaporemath.com/Earlybird_Kindergarten_Math_STD_ED_Activity_Bk_A_p/ebstdaa.htm I know it says kindergarten. However, it seems to work well for prek also. My dd wanted schoolwork "too" at the time, so we ordered this (and book B). We liked it because it wasn't just writing and copying. There were lots of activities that involved cutting and glue. She loved cutting and glue.
If my kids were little enough I would do All About Reading because I loved their spelling program so much. However, we did use the books before the Explode the Code books. These are called Ready for the Code, Get Set for the Code, and Go for the Code. They were great at introducing the consonants and consonant sounds. (Vowel sounds get done in Explode the Code). I like how it wasn't just writing letters over and over like with some prek workbooks. Here is a link: http://www.rainbowresource.com/searchspring.php?q=getting+ready+for+the+code
However, my kids loved the Melissa and Doug "Number Train" and "Alphabet Train" puzzles. I would scatter the pieces and they would hunt for the next one. . . what comes after 1? Let's see if we can find it? Etc. http://www.rainbowresource.com/product/sku/012540/ff09d197f1450a3b33ea7a27
My kids did like to have workbooks, so we had some hidden picture and some early mazes around. We also read a lot, did lots of puzzles, played outside, cooked, played dress up, pretend, danced, etc. I gave them lots of time to play uninterrupted and unguided. They learn well that way. They have also enjoyed helping with the garden, our pets, etc.
We are planning Right Start A and the Ordinary Parent's Guide to Teaching Reading for DD this fall. Beyond that, she's always tagging along with her big brother who will be doing the full contingent of school work (math, LA, history, science, art, music, etc.) this fall.
I have not heard of Alpha-Phonics (I just looked it up though). It sounds pretty good. One thing about Explode the code is that I found that it went well with other programs. My middle child used it as review, it was never her spine. I don't see why they couldn't be used together.
littleacornlearning.com best prek program out there IMHO. it is waldorf flavored so very light and easy to incorporate in to a real life rhythm. I think they still have 2 weeks you can download for free on their website.