ABC book on handling and breaking horses is good to start the stuff M...eldy is suggesting, but def use a experienced horse breaker, may cost but in the long run it will be worth it. Find someone using word of mouth preferably, the best breakers are normally the ones working away quietly at. Good luck
Long drags both up and down with good stretches of reasonable flat (this was from car). Plodders will manage it, plodders manage anything, I should know. Good luck and enjoy, I'll be there.