Sine the pattern suggests that you bind off without any decreases, it would appear that the neckline would be what most would consider a "boatneck". You will need to determine how large an opening you want - I think 12-13 inches on both front and back should be sufficient. Based on your gauge, I would determine how many stitches you will need for your measurement, deduct that from the total stitches, then knit one half of the number of remaining stitches, bind off the number for your neckline, knit to the end of the row. On the next row, knit to the last bound off stitch, cast on the same number of stitches you bound off, knit to the end of the row. On the remaining rows, decrease stitches at the same rate that you increased them on the first piece.

Thank you, Donna...do you think I can cast on those stitches on the NEXT row (like a button-hole) without knitting a few rows for a 'wider' opening? Of course that would mean using new balls of yarn for the opposite side of the opening then joining them, casting on the needed stitches in the middle. Not something I'm anxious to do...but really...even if I did them as two triangles there would only be a 'button-hole' type opening anyway, right?
Did I just talk myself into that method? ;-D

I may not have explained myself clearly, or maybe you're not understanding correctly. The buttonhole method is exactly what I am suggesting. And there is no need to use another ball of yarn when you begin the opposite side of the opening. After binding off and knitting to the end of the row, turn and knit to the last bound off stitch (which is now the FIRST stitch of the opening) and cast on the same number of stitches you bound off, then knit to the end of the row. Hopefully this is a little clearer. Feel free to email me if you have any questions.

I think it was me who confused you...;-)
The other ball of yarn is used when you have to cast off the neckline stitches, then knit several new rows before casting on again...sortof like creating a shoulder part. The neckline that way is wider, rather than 1 row wide, it might be 5 rows wide.
But yes...I'll use the "buttonhole" method you suggested; much easier and with your reassurance that it won't be too 'tight', I'll go for it. I'm thinking 30 sts is a good amount, judging by other sweater patterns on line...
I did the front piece in two evenings...so this actually WILL be done by Christmas!

Thanks, Donna, for all your help...I sincerely appreciate it!;-D

My pleasure.