I can't see where using that fanfold would be worth the effort. It's r value is only 1. Use the 4x8 sheets of at least 1/2 inch thickness to get some insulation benefit for your $.

Well, the plywood has definitely got to go. Is there provision for venting the crawlspace? If it is too tightly sealed, the natural dampness can't escape.

With the A/C, first thing to do is be sure your condenser and evaporator coils are clean. Also, make sure your duct work is intact, perhaps by using a mirror and flashlight to look down through the (removed) floor registers. Be sure the duct work is sealed to the register outlets too, You can use ei...

Yes, go with vinyl in the bathrooms. Much easier to clean up "accidents." How bad is the marriage joint? Could it be sanded down, or a liquid leveling compound be used? I would try to get the joint as smooth as possible, even under carpet. As for transitions, you could fasten down some scr...

If your faucet is on an outside wall, then I would guess you would have to remove the exterior siding to get to it. If the siding is separated there, that is likely the access point. What type of screws do you have? I'm guessing they have a square hole? There are square bits available. The square dr...

You should be fine for a couple of loads. Just get it extended outside ASAP. Hopefully your skirting is vented, so the moisture will eventually dissipate.

PEX is also used in stick built homes. We had copper stolen from our church camp, and replaced it all with PEX. It's great stuff.

Welcome! You will have to fill the gap with something, or you will eventually have a dip there showing through the planking. Place a straight edge across the marriage line and slide it along the length of the room to see if there is any difference in height from side to side you will have to make up...

Yes. It will keep moisture down, and makes crawling around under there a little easier.

At least you have shut offs, a good many don't.

IIRC the drain should unscrew from the top by wedging a couple of screwdrivers through the drain grate and using them as levers to turn it.

Trim on mine is stapled to the edge of the counter top. Either use the knife, or remove the counter top to pull the staples.

Nope, the Valspar won't cover it. Been there, tried that. You need a primer. Plus, any stains will bleed through. Use the Kilz.

With the thin walls, , I would guess that the cooler interior is mostly due to the white exterior. Hopefully the roof is a light color too. That will greatly reduce heat gain. The hvac unit I was referring to is self contained, and would sit on the ground outside the home.I suggested that, because i...

It seems like quite a reasonable project. For the hvac, there are package units available that would only require duct work reinstalled. Seems like that would be cheaper to run than window units.