Let's say you didn't listen to me and you forgot to bring along a power strip. Older hotels and cheaper motels often lack enough wall outlets for plugging in all a business traveler's mobile electronics.
I've found that you can usually hunt around for outlets and at least prioritize how to best use them. You can unplug the TV for an extra spot, or the plug the heat/AC unit uses. There are also usually plugs for the bedside lamps and the bedside clock radio. So think about what you need least and unplug those first.
There is usually a plug in the bathroom as well, which might have a coffeepot or hair dryer plugged in. REALLY old motels may not even have a bathroom plug at all.
I have been known to pull beds and entertainment units away from walls to find outlets. It's at least worth a shot.
Of course, if all you find are two-hole outlet plugs, you may just be out of luck. If so, you may consider yourself "roughing it". Maybe you can use the lobby outlets, or go find a library or a coffeeshop to work in!