I have the Japanese Heart Gold, and it really is just like Pokemon Gold. Just of course updated for the DS, and that it does have all the same TM/HM's from the three previous games. It would of been nice to have some old school moves like "headbutt", but I believe we can live without it. Plus pressing the A button on a tree shakes it for you, or at least what I can tell.
The scenery is far better then the previous three in my opinion.
I would assume they'd be at the Battle Frontier, but I am only at the third badge in the game as of now. College kinda slows things down.