With any dog, be REALLY careful not to overdo it.
A mate of mine rode daily with his year old black lab and totally killed it’s hips.
I have ridden with mine a few times (extremely fit black lab) but I just think riding pace is too fast – the dog is belting it the whole way and on a ride worth having (10+ miles) it’s too much. If the terrain is VERY off road, it’s going to be better as dogs think nothing of bounding up and down hills and technical terrain and can keep up.
I’d favour a collie or a springer spaniel for riding with. Excellent stamina. Really fast dogs will tire too quickly – they’re a bit like cheetahs.