I would much much rather cruise a closed freeway on a bicycle than to sit in the house pedaling, myself. Especially if several hundred other cyclists are out there.
I don't know about the Houston ride, but the Dallas ride seems to be set up to be a "see Dallas" ride rather than a "cruise through the country" ride. I plan to do the Dallas ride here in a month or so. Of course, I've been on part of the course already.
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"be careful this rando stuff is addictive and dan's the 'pusher'."