Cooking pork roast ahead of time for Christmas?

I need to take a rolled loin pork roast to Christmas lunch. I will cook it at home and take it with me but we will not be eating until an hour after we arrive. My question is, how do I cook the roast to ensure it stays tender and the cracklings stays crispy 2 hours after taking it out of the oven? Or, is there a recipe to pre half cook it and finish it off at the location just before lunch? I don't cook pork much so I'm quite nervous!!

Thanks so much!!!