I bought a new car in a town 50 miles away in the 1990s, found a warning like that (not 50 MPH, but don't maintain steady speeds) when I read the manual after getting home. Also learned it wanted 89 octane gas but would degrade max performance to run on 87.
If you can do the 500 before towing, don't sweat the first 500 of towing. Especially if you can do 1000 miles of varied driving before towing. Break-in "restrictions" are actually a lot less strict than they were 50-60 years ago, but we ignored them back then as well. We did usually do the 500-1000 mile break-in oil change (seldom required now and 3000-5000 more likely) before going to the regular (1000 or 2000 mile) schedule.
With modern metallurgy and lubricant technology, the break-in period for some components will be a few hundred to a couple thousand miles, for others (engine particularly) it will be in the tens of thousands. However, today, there are no longer issues with break-in lubricants that allow fast wear then need to be changed, although my Dodge dealer pulled that one on me with a one-time need to change the axle lubricants on a 2004 4x4 vehicle.
And who, besides us OCD engineering types, actually reads owner's manuals? My daughter just bought a car with 137,000 miles on it, I was the one who read the manual. She didn't know she got one with the car, so she didn't know it wanted 89 octane.