BREAK-IN PERIOD FOR 2000 4RUNNER

I have a 2000 4runner (5 speed). It now has 548 miles. The operations manual advised to drive it not beyond 55 mph at varying speeds for the first 1000 miles. When I went to the mechanic at the dealership, he told me otherwise. He advised me to drive it as I normally do (70-80 mph) but just drive on different speeds.

Also the manual recommends oil change at either 5000 or 7500-mile intervals. But the mechanic advised me to do the the 7500 interval but change the oil when it hit 3750 (half of 7500). Then another mechanic told me to change the oil on the 1000th mile. I don't off-road and I don't tow.

What do you guys think?