That is one tough job to do. It is an extreme amount of work to get the old floor surface smooth enough to put asphalt tile or roll flooring (vinyl or linoleum) over it. There was another thread or two recently covering removing old tile. Easiest way is just to cover with luan, fill the seams, and install new flooring. If it is going to be carpet just fill in any broken or missing tiles then install pad then carpet & be on your way.