Thanks, Travel4Free:
The main point is to do a midweek out and back from EWR to SFO without paying $2,200. Thus, the separate, RT tickets to LAS, where no Saturday night stay is required.
I agree wholeheartedly the the best way to harvest miles is: EWR-DTW-CLE-DFW-IAH-LAS and return. I typically do EWR-IAH-LAS, sometimes EWR-CLE-IAH-LAS if I can get the cheap RT fare with the extra stops. I guess I just need to work a little harder to get DTW (ugh!!) and DFW in there as well. Thanks for the tips.