If you are on the metro Red Line (DuPont cir), then MD suburb red line stations are probably easier for you. Possibly easier for them to not go inside the Beltway too. Arlington is not exactly 18-wheeler friendly, even if there might be a few large parking lots. OTOH you are paying them and there are roads they are allowed to use. If you wanted to choose the Potomac Yard area with the Target, you should know it is quite a walk from the nearest Metro stations.

Wheaton on Red line is a good choice for the truck driver if coming from the North via I-95 but not as good for you. Grosvenor-Strathmore is the first Red Line station on DuPont side that has a parking lot, which suggests there should be other parking lots near there. Medical Center is a bad choice, for example, because the parking is inside NIH gates.

From the Virginia side, I would say somewhere on Silver line (between McLean to Spring Hill) will work. Lots of office parks, but you might have to walk a bit depending on what parking lot they find.

If you're going to get your car from the suburbs, you might want to get gas there too where it will usually be cheaper than in DC.

I found my stylus which was in a pencil caddy and the sliding/dragging action works fine.

I don't have mittens, but if I put my hand with the four fingers opposing the thumb, then I am able to hold the stylus in a winter glove. Feels a bit awkward, but definitely able to use the phone. You can't do multi-finger gestures though and that could be useful to zoom in/out on a map.

You coud get a stylus pen at Dollar Tree (for $1.25). I am not sure if they work well for the action of sliding a finger. And it is easy to misplace the stylus pen. I would try out the sliding finger action, except I don't remember where I put my stylus.