I'm assuming the urine is in the padding.  

Not just musty dog smell but a stronger one, like urine.  

Not only that but a powerful smell of cat urine from the 7 cats i counted as they ran passed me when i entered the front door!

Also if it had glue or urine damage it wont refinish well.

@Frank Mourad don't worry about that hurtle until you get there.

First learn to deal with the pet urine:http://www.biggerpockets.com/forums/67/topics/48302-dealing-with-pet-urine-in-plywood-subfloorOnly an investor would be likely to buy such a house.

There's old cat feces everywhere, noticeable urine stains, scratched up walls, black mold on the walls, rotten window sills, doors made out of wood and chicken wire that apparently were built to block off hallways, a tree partially through the roof in the living room, holes in the walls in some places, refrigerators that are beyond disgusting and vanities that are barely standing among other issues.The place has a lot of potential I think once it's cleaned up but I've never tackled this kind of situation before.

They believe the hurtle is SO BIG that becoming "rich" or "financially independent" is not within their realm.

I too had tenants who dragged things across my hardwood floors and who let their dog defecate, urinate, and vomit all over my nice wood floors.

I always thought it would be cool to install a urinal in my house.