Most highways are still impassable, especially the feeder roads. It's more dangerous to get on the roads than to stay put. We keep seeing footage of people driving on the wrong side of the freeways because it's the only way to get through certain stretches.
I was one of the people who evacuated from Houston to Austin in 2005. What would normally have taken 2-1/2 hours took about 9 hours. There was no gas at all along the route, it was over 100 degrees, and no places open along the route to stop to go to get food or go to the bathroom. It was a nightmare and many, many cars were abandoned along the side of the road as they ran out of gas. It was a nightmare. And that's not to mention how a city can effectively evacuate the medically frail, indigent and elderly.
We went to Barcelona this spring for 9 days and it was wonderful. The city is interesting, the architecture is beautiful and the food is wonderful and relatively inexpensive. We mostly did non-touristy things -- while Park Guell and Sagrada Familia were cool, they weren't our favorite parts. Avoid Las Ramblas (ridiculously crowded and touristy and lots of pickpockets).
I also loved taking a day trip to Girona by train. Tip -- go to the local department store's travel agency (El Corte Ingles) to purchase train tickets (as it's much more straight-forward). There is a high speed train that travels between the 2 cities in about 37 minutes.