One place I've gone to about 3 times has 15 miles of washboard roads. I don't go any faster than 8-11 miles a hour and though it does take some time to get there that last leg of the trip, I have not had ANY issues as a result.
I would in the strongest possible terms suggest that you consider mudflap or an enkay type hitch mud flap (or both) to reduce the projectiles that can fly off the rear wheels of the tow vehicle into the trailer.
Computers manufactured by companies such as IBM, Compaq and millions of others are by far the most popular with about 70 million machines in use worldwide. Macintosh fans note that cockroaches are far more numerous than humans and that numbers alone do not denote a higher life form. -NY Times 11/91