It has a tongue and groove screened in porch that is in good condition except for some significant wood rot at the junction where the porch joins the landing to the steps. 

Grooved Edge Capped Composite Decking Board in Brazilian Walnut The floor area was 7 feet X 18 Feet.

If you're curious, Google Janka Hardness Scale (cool stuff for a construction junkie like me).On another note, given the (end grain) photo - it looks like they didn't use tongue-and-groove boards, which is typical of finished wood flooring then and today (or did you cut them off). 

If you do repaint it might be a good idea to fill the grooves in the paneling and retexture to match the other walls.

Get tongue and groove pine at Home Depot for the door and regular pine planks for the pieces to hold the door together.

Gary - there are quite a few waterproof laminate tongue/groove styles out there, including the Quick Step brand.

Profile and Core Types• Various options including solid strand, solid strand floating, tongue and groove engineered, click-lock engineered, solid horizontal and solid vertical.

I actually like the look of the painted paneling, because of the grooves.

@Chris Mason That will happen at some point, but we are in a groove and it is working very well into our quality of life by staying here.

My thoughts are at the beginning, you need to make money and reinvest, make money, reinvest, until you get settled into your groove.