Well, I'd either do the buddy thing, or save all that meat that they would've eat for myself later down the road! Haha, but I'd probably buy a really good fish, maybe swordfish, and grill that. If not fish though, I'd go with lamb. God I love lamb. Or I'd get something nuts like heart or a good offal cut since I bet she wouldn't normally let ya cook that for y'all! Experimenting is fun fun fun.
I'd probably load the smoker up with something that would be done when she gets back and have dinner ready. That would get you some brownie points if she came home to a clean house and a wicked meal! Give you something to tend to as well since grilling is somewhat of short term, short lived enjoyment.
I don't know whether I'm lucky to be single, or out of luck since I don't have a girl to cook for ever. LOL.
Weber Spirit E-310, Weber Performer, Weber Smokey Joe, Mini-WSM, ECB Electric.