One thing to remind yourself is you get nervous is that wherever you're driving, other women drive, transport furniture, live, shop and do a variety of other things everyday. The only time I have had anyone remark on an out of state plate--from a good distance--was a Babies R' Us in Utah, in broad daylight, and it was a family who parked next to us who had fond memories of spending time in Boston when younger.

It sounds so trite, but just use common sense. I personally prefer to limit/avoid late night driving, and take care not to fall into "Hey, look at me! I'm all alone, and this is where I'm staying tonight." kind of behavior.

I also use a GPS. If you don't have one, and can afford it, I highly recco it. That way, you're not as likely to be pulled over to the side of a road, engrossed in/arguing over a map---which might make you a *tiny* bit more obvious. Also, take care not to broadcast your itinerary in restaurants or other public places, since you never know who is listening. (You can certainly strike up conversation with friendly people, I just say I'm "on vacation, and location X has been a blast/beautiful so far. " instead of "I'm driving cross country and the next stop is _____")