Replacing sheet vinyl with rigid vinyl planking

If the floor is soft do not use any kind of snap together flooring. When the floor flexes the joints will come apart. Pull up what you you have. Cut out the rotten floor and replace it with solid plywood. If you intend to use it as a deer camp you will need to fix the floor anyhow. Once you have the floor fixed you can put down the vinyl planking. Or even the 1 x 1 sticky tiles.