About 260 miles.
No
It is 172.88 miles according to MapQuest.
The Arlington National Cemetery is directly across the Potomac, about 3 miles from downtown Washington.
Basically, the width of the Colombia river. It's a two minute drive over the bridge before you're in Oregon, and another 10 minutes you're in downtown Portland, which must come as a welcome relief if one has previously been in Vancouver, Washington. If you've managed to leave Vancouver and make it Portland, I don't recommend returning. Stay in Portland, and enjoy the amazing city that it is.
It is 158 miles according to Google Maps.
It is 262 miles according to Google Maps.
Portland, Oregon is located right on the Columbia River ( or next to) . The Columbia river forms the border between Washington state and Oregon. So, Portland is very near the Washington state line. The City of Vancouver, Washington is just north over the WAsh/Ore border or just over the Columbia River.
Which Portland?
The best option for a good cheap hotel is the Red Roof Inn. This is a little far from downtown but is a great hotel.
It is 963 miles to Portland, Oregon from Los Angeles, California.
Downtown Houston is 50 miles from Downtown Galveston.