I'd like to improve my fitness gradually and was thinking of going for a walk every night at the field/ rec ground across the road.
Dog owners, would it be crazy to ask my neighbours if they'd let me walk their dog some evenings?
I haven't walked a dog since I was a child and I'm wondering if I've overlooked any factors other than them saying no, which is of course completely fine 
They have a young family (incl. young twins) and I haven't noticed the dog being walked, not to say they don't walk him.
The dog is a labrador/ cross, I'd hazard a guess at middle-aged.
I have no idea of his temperament (e.g. around other dogs). Is it acceptable to walk him on a lead? I'd feel nervous of him running off otherwise. What's the etiquette if another dog comes over for a sniff and upsets him 
Sorry for all the hypothetical questions 