Ok...as for "me" I think you've got problems brewing. Not from a safety standpoint, but choice of meats.
The pork loin is difficult to smoke and like. It dries out pretty darned quick. A 5 hour hold won't help that much.
"I" would roast the loin...ok, smoke it for a while if you want to present sumpin' from your smoker, but I like them roasted at a higher temp. "Low and slow" seems to drain all the juices, and there is no fat to render. I'd take my loin chilled, wrapped in foil, get to where I'm going, slice it thin and reheat for sandwiches in a broth/butter/worcestershire bath and serve on fresh buns.
As far as the tri-tip. Take it raw, build a fire in their fireplace, or wood fire in the backyard, or? and cook it like a steak... which, by the way, it is.
OR...smoke a pork butt, which everyone will love and can easily be transported and kept warm, AND do a chuck roast in your CS for the non-pork eaters. You will dazzle 'em!!!
My thoughts are more about good food, rather than food safety on this one.
Hope my 2 cents helps. Whatever you choose let the group know...so as to run out and do the same, or avoid in the future.