We have a staff who loves coming out, 15 miles is about his safe max. As others have said the dog will keep running till he drops so be careful.
As for training, lots of short rides around a local field drumming in recall and heel/close training. If it gets excited then put it back on the lead till it calms down. If it walks in front of you just ride into it(slowly), same if it stands across your path, its a dominance thing so make it get out of your way, even if that means a collision. It will soon learn not to get in the way and be bike aware. Consistency and being pack leader is key.
I usually do a 9 mile flog-myself-to-death-session on the onespeed that kills me and the dog just shrugs it off.