What VFR cruising altitude should be flown to the west below 4500 feet?
Yes, you would have to comply with §§91.159.  If you’re flying VFR westbound (180°-359° magnetic) at >3000 ft AGL,  you will need to fly at even thousands + 500 ft, except while in a holding pattern or turning.  For a forecast of scattered clouds, you will simply deviate from your course for cloud avoidance, then return to the route.