Brain Fog...Mathamatically am I OK changing these directions?
 

Directions tell me to cut 142 light, and 142 dark 3-7/8" squares. Put them right sides together and then cut in half diagonally, then sew them together using a 1/4 seam allowance. Can I just sew them together, 1/4" on either side of the diagonal, then cut apart? The next step is to cut 1152 2" squares and sew 4 x 4 rows to make a 16 patch. Why not sew four long, two inch wide strips together, then cut at two inch intervals and sew randomly together for the 16 patch? I'm thinking it will all come out the same, but am I missing something basic??

Your way will work fine; you're not missing anything!

You can make HSTs 8 at a time, much quicker. For 1 1/2" unfinished HSTs cut 4" squares, mark two diagonal lines and sew either side, cut side-to-side and top to bottom from the edge centre, then on the marked lines. Trim to size.
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For the 16 patch, sewing strips would also be much easier and quicker.

Yes, you will get 2 HST's, and with the measurements you gave, you'll square them to 3 1/2", but I always add an inch instead of 7/8, because sometimes the 7/8 measures means that your block is sometimes a little "skimpy".

I would use 4 inch squares for the HST's and then trim to size.
For the 16 patch squares I would sew 2 1/2" strips in sets of four then cut 2 1/2" pieces toss every thing together then sew into 16 patch blocks - should turn out pretty random. OR you could just sew 2 1/2" strips into sets of 8 - then sew into a tube like you would for a bargello. Cut into 2 1/2" tubes and pick out a seam at random then pick out the middle seam to get your random 4 patch strips. Again toss these together then pull out by 4's to sew into the 16 patch blocks.