
Once he has had a vet check and all is fine if he is an adult then here are some tips that I use to get my noise phobic (severe) dog out side the front door.
1. Being fed out side. If this is too hard start in the hall then with the door open then close to the door then outside etc... until he goes down the road excited for his food.
2. You say he walks best with two people. Get his favourite person to walk about 20m ahead or until he is desperate to get to them. Give a command ie walkies and then let him go to the other person. Reward either on route or when he gets there. Then start again. This can eventually lead to longer and longer distances between the people and not such great rewards when he gets there. Soon you can get the person to walk out the house and then hide and then he should walk the set route around and back to the house at which point he gets rewarded.
3.Other things are driving him to a point of the walk and then taking him out and walking the rest. Or if that is too diffiicult. Take him somewhere in the car and then walk home so he knows he is going home instead of going on a walk. Don't let him pull you home though.
I find that giving walking a command helps as it gives them something to think about. Also train some tricks or fun training that he enjoys and instead of trying to walk do some of these on the streets and gradually walk to each next trick. This will get him thinking about the training and not walking. Clicker training is brilliant for this also. Try and train tricks that move ie weaving through your legs, turning in circles, tummy crawls along the ground, if he does agility i use the forward command (in my case go go go!!!) which really gets my dog excited and i therefore allow her to pull on the lead forwards and sometimes run.
I hope these tips help
My dogs still doesn't walk very far but she was very very set in her ways and really scared when i started so for you it should take less long and be easier.
Don't make an issue of it and if it isn't getting anywhere sometimes not walking them for a couple of days (just stimulating indoors) can get them eager to get out and that is when the training can start.
Best Wishes
Anna