Hi, Scoops.
Using I-40 as an alternative to I-70 in the hope of avoiding snow is a subject that gets discussed here every winter. The problem with this idea is that just because I-40 is a more southerly route doesn’t mean that there won’t be any snow. I-40 is above 5000 ft. 2/3 of the way across New Mexico and Arizona, reaching elevations over 7000 ft. at several places. (see map below)
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Also, I-25 sees plenty of snowy weather, as it runs right along the western edge of the Rocky Mountains.
Now, with all that said, in mid-March the weather might not be all that bad. There’s a chance that you could see some snow, but you never know. Springtime weather is very unpredictable around here, except for the wind -- you can pretty much count on that.
As far as places of interest along the way, the Grand Canyon springs to mind. There is also a good article about other places near the Grand Canyon here on RTA. You may want to look through this thread as well. Once you get some idea of places you might want to visit, come back and we’ll try to help you plan your trip.