Easy way is to cut the carpet along the edge of the dinette, put down the new carper and then cover the edges with 1/4 round.
For the main floor, you may want to consider water resistant, floating hardwood flooring. Or, just cut a piece of carpet to lay down. You can either secure with 1/4 round or leave loose so it can be removed for beating out the dirt. The removable carpet is what I did to the floor of mine. Makes it a tad bit warmer and nicer to walk on without shoes. Has lasted about six years, but now I need to get another piece to replace it.