What you are thinking for the fronts sounds pretty good to me. Should work. You need to keep your cables close to the center opening on each side so that the increases as you make the sweater bigger don't affect the cables.
On the sleeves you will work the yoke section enlarging as you go until you have 42 stitches between markers for the sleeve sections. Then you knit those 42 off onto dpns and add 6 stitches under the arms to have a total of 48. What she says about how to divide the sleeve stitches up on the 3 needles is not that critical. What she says may work fine, but if you find that the center 8 that you want to be your cable are divided between two needles, move them around until they are all on the same needle for easier working. You will have 20 stitches from center of armpit to where the cable begins and then the 8 for the cable and then another 20 back down to the armpit. You can set your 8 cable stitches off with markers at first if you need to, but soon you will see them just fine. You are working the sleeves in the round so to get stockinette stitch just knit every row, ignoring where she says to purl some rows. Do the decreases as given at the underarm seam and keep your cable going down the middle. Should work.
The fact that you are leaving out the purl rows will probably affect the number of rows you need to get the length you want for the body and the sleeves. It may make the yoke a bit longer than you are expecting too since throwing in the occasional purl row pulls things in and shortens them. I think it will still work though. If you find it is getting longer in the yoke than you think it should you could probably just stop at that point and divide for the sleeves to begin there. Unless that would make the sleeves too small, then you will have to make a decision what to do. The exact number it says to have for the sleeve isn't something that has to be set in stone, but you need the sleeve to have enough stitches in it to make it roomy enough. You could also decrease a bit slower than it says, if you start off with fewer stitches. Wing it a bit. It's fun and you learn a lot. You may also get opportunities to frog. :-) Happens to me a lot.
Good luck and have fun with your project.