Insulation issues

Ugh.  I'm building a little home for a loved one.  Long story.  Bought a mobile home very used.  Probably spent too much because I have to tear it all the way down and rebuild.  Another long story.  Anyway, I've spent the summer trying to learn the theory of how to frame and plumb and wire.  I live in Massachusetts.  The insulation requirements are... a lot.  This means that the cavities created by framing for the floor and ceiling or roof need to be deep.  Very deep.  I can't afford VIP boards even if I could find them.  I can't afford I joists to reduce the weight.  

I need some affordable options to keep this home warm in winter, cool in summer, and keep energy usage low.  I also don't have a lot of time to faff around with pie-in-the-sky designs because he needs this house yesterday.  The situation is not good.  I need quick and dirty that will be good for long term use.  I don't need a disposable option.  This thing will never move from this spot.

I'd appreciate whatever help/guidance y'all can offer.

Recommended to have r19+ in walls, r30+ in floor, r38+(up to r60) in roof (that's 17"!!).  Single wide mobile home is 16x65 finished.  This thing was not constructed for New England.  Trying to not overload the frame (even though it won't go anywhere from here).  There will be a fridge, a cooktop/oven (hopefully gas on gas or dual fuel for cooking and heating).  I'll be removing a furnace (replacing with a combination of electric and gas on gas) , a big hot water heater (replacing with tankless), and removing the washer/dryer because he can use the ones in the main house.  Other than that, just regular live weight stuff - beds, sofa, dining table, kitchen cabinets, tiled bathroom with sink and composting toilet.

Thanks heaps,

I'm going to say, if you want quick and dirty then go with batt insulation. Mineral wool batts are my recommendation over fiberglass.

The biggest area that a lot of cold seeps in on mobile homes is the floor. Use material that is not easily flammable because if a mobile home catches fire you have seconds to get out before the whole thing is lit up.

A non-permie option that might be worth looking into is spray foam. Paying for that, since it'll be done quick, won't weigh much, and is airtight, might be worth it.

No, it's not the best option as far as organic etc. But neither is freezing in MA, and needs to be done yesterday.

I'd caution against spray foam in any cavities where there isn't ventilation, because the stuff traps moisture like nobody's business. In a trailer or mobile home, this will be a precursor to mold and rot. Batts where you have good access and blown material, such as cellulose, in the rest.

If the whole thing is a temporary solution and you don't care about aesthetics, you could put a second skin around it in the form of a tunnel house.

For anything that is not super high-tech and expensive, you will need more space in the walls than you started with. I presume you ripped out the original interior finish, and will be refinishing with drywall. Furring out the existing framing with 2x2, 2x3 or 2x4 depending on requirements is the most practical option and probably cheapest. You don't need thicker than that for the walls.

For the roof, what condition is it in? If it has leaks or looks iffy, your best bet might be to add 2x4 framing on top (well anchored and spaced up a bit to fit insulation) and fill with fiberglass or mineral wool before putting shingles or metal roofing on. If the roof is good, how high are the existing ceilings? How tall does the space need to be? How many ceiling fixtures are there? (Any electrical boxes in the ceiling will have to remain accessible after any interior refinishing.)

I would definitely add insulation in the floor as there is likely little there. Fiber batts would be by far the easiest to fit in place, and I would protect it with wire mesh to keep critters from getting in and making big holes and nests. A solid continuous covering would be good. I would strongly consider solid skirting all around the perimeter (with an access hatch) to keep the wind out and the floor much warmer in winter weather.