I don't know why you avoided the highway. I guess "take it easy" means different things to different people. They didn't mean not to operate the engine at highway speeds. They meant that you shouldn't be drag-racing cops or climbing mountain passes at full throttle.
Since you've achieved 1000 miles, go ahead and dump the factory fill and put in some good-quality dino or synthetic oil, and drive it like you want to. I'm sure the next post from someone else will warn you against dumping the factory fill early, so I don't even know why I bothered saying it...but it won't hurt anything. I've been doing it for years, to my Hondas and the rest, and I've never had an oil burner or an engine failure from it.
Honda engines are some of the best out there, you're not going to hurt it...especially now. It's actually too bad you've babied it to this extent, because it's actually better to work your way up the tach as you put on miles. You could've driven it on the highway straight off the dealership floor.
My $.02