Finish cooking a stuffed pork roast if I turn it off for a while

Your ribs were undercooked. Time is a guideline in barbecue, not an absolute. The folksy rule of thumb is "the meat will tell you when it's ready." Rather than watching a clock and taking the ribs out when a certain amount of time has elapsed, you should pick a time when you will start checking your ribs to see if they are done, and keep cooking them until finished. These are your cues:

1. Sight test - the meat on the ribs should pull back from the end of the bones considerably, usually around a half inch.
2. Bend test - if you pick up one end of your rack of ribs with a pair of tongs, the rack should be able to bend easily.
3. Probe test - you should be able to slide a skewer through the meat between the bones with VERY little resistance, if any.
4. Tear test - the meat between the bones should tear easily with just your fingers.

As far as reheating, it is possible. I would suggest wrapping them in foil, and perhaps putting some liquid in the bottom of the foil pack. It will not be as good as if you had cooked them in one stint, but it should still work.

What I personally do is the following:

Note: I assume you want it well done and not rare. I would not recommend cooking the loin in 2 shots if you want it rare.

First, when cooking the day before, stop cooking the peice before you consider it cook as you would eat it. i.e. If your cook time for done is 1h, cook it 50 minutes.

Note: for best flavor, I highly recommend you keep the fond

On the re-heat day:

• Let the meat sit at room teperature for 2 hours.
• Preheat the oven or bbq to 300f
• In a large enough cookware with a lid or alluminium pan (I would double it up to prevent spill) and air thight foil as lid, put a layer of 1-2 cm of 50% sauce + 50% water + some butter or olive oil.
• With a spoon, pour some liquid mixture you just created over the piece.
• Oven it for 30 minutes, then redo the liquid pouring step while making sure it's wet enough, it not, add some more water.
• Depending on the size of the piece it should take 1-2 hours to be perfect.