I wouldn't recommend strength training 6 days a week. Less is usually better. I would recommend Mon/Weds/Fri on strength training, Tues & Thurs some short intense cardio like HIIT, Sprints, Tabatas, complexes, etc and long slow cardio or GPP (a hike is good, so is yard work) on Saturday and active rest on Sunday.
Even splitting push/pull, which is what I think you are doing, is too much without taking at least 1 day off out of three. There are still muscles that overlap in some push and pull exercises. You will wind up trashing your shoulders and you will not be able to train with sufficient intensity to actually improve much. Upper/Lower would be a better split but you still need a day off now and then. i.e 2 on, 1 off.
I think the best way to work abs is by squating and deadlifting, including variations, some light sittups and extentions in your warmup and some twisting motion and any other heavy ab work at the end of the workout. If you want to be efficient in your workout design, train antagonistic movements back to back in superset form, such as bench press/Bent Row or OH Press/Chin Up, etc.
If you deadlift regularly and train instensly with the upper body push and pull exercises you really don't have to train forearms, biceps and triceps much. If you want add a set at the end of your workouts on Friday.
i think i will do the upper/lower split. i think i will do two on one off. i been running home from the gym everytime its about 2 mile. you think that a good cardio. i'm 5 2" and about 125. i want to gain another 15lb of muscle mass.i been actively working out for 2.5 month and notice my arms are way bigger compare to my body so i came back here for help. i been working out with a friends and doing his workout. notice my upper back, and arms got bigger but not my lower back. so i'm putting dead lift and squats into the workout.