Phoenix, San Diego, Las Vegas, Grand Canyon, Phoenix. Is this too much to drive and sightsee in a week? in February? If so, what should we drop off our plan. Is the Grand Canyon worth seeing in winter?

If it were me, I would stick with Arizona. There are a lot of things to see between Phoenix and the Grand Canyon. My family did the Grand Canyon just before Christmas a few years ago. Very enjoyable time with many fewer people.

You could spend time in Sedona, see Montezuma's Castle, Sunset Crater and more with a lot less driving.

Oh yes, i think that is too much for one week. If you are flying into Phoenix, stay in Arizona for the week. The scenery is stunning and so different from the east and midwest sections of the continent that you will be amazed. As Suzie says, see Sedona and perhaps stop in Jerome on the way up to Sedona and the Grand Canyon. You could also travel east from the GC and see Canyon de Chelly. Do a search on here for more info on these places.

I assume you already have your flights booked in/out of Phoenix. If so, I totally agree w/ the others - just stick to Ariz.

If by chance you haven't bought your tix yet, then open jaw into Phoenix and out of San Diego w/ the Grand Canyon in between could be a reasonable week (dropping Las vegas)

Or in to Phoenix and out of LV (dropping San Diego) would also be reasonable.

Thank you for the responses, it was exactly what we needed to know.
Another question, as we are going in February what could we expect the driving conditions to be, enroute to the Grand Canyon? Cold and damp? or snow?