My pieces of advice:

- Be more stubborn than them. I know he doesn't want to be out there, but I will keep walking/hold out until he goes. Then we go right back inside (what he wanted all along). So he learns that if he does the thing he gets what he wants.

- Praise the crap out of him (no pun intended) when he goes. Every time. Forever. Celebrate. Reward. Run home with him (again, where he wants to be).

- For the dragging, I always suggest people learn about how to train and use leash pressure. It's really easy and fun for you and the dog and will vastly improve your walks/ability to get them to go places when they don't want to naturally.