what goes with pork tenderloin?

You don't say how you prepare your tenderloin.  (*)

If you use anything that has a sweet/sour, or fruity touch to it, I would serve it with a modified rice pilaf. Rice pairs well with sweet/sour.   Nothing too fancy for the pilaf, just cook your rice in a little butter (only to coat all of the grains), before you add your liquid.  AND, make about 1/2 of the liquid a low-sodium beef stock.  

Another good accompaniment for any pork, is scalloped potatoes.  (I wouldn't add cheese, which can make it too rich.)  Do layers of sliced potatoes.  Over heat, mix; milk, butter, flour, herbs of choice and salt/pepper.  Pour over the potatoes, and bake, in a medium oven for 45 minutes, or so.  The top should be browned.  There are a gazillion variations on YouTube. 

Unless the salad is the main entree (like a seafood salad), I think should be simple. I don't know where your are, in the geographic scheme of things, but use what's seasonal where you are.  Toss in some chopped walnuts, or pecans, for an accent.  You can't go wrong with oil and red wine vinegar, to mix. 

Cocktail pairing is a "toughie."  The only cocktail that I really know is a Manhattan ... I'd  have one of those with breakfast cereal. 

If they don't care for wine, and you're going to have cocktail-like drinks with dinner, you might consider having a bottle of "flavored" vodka, in a bucket of ice.  I know that there are a lot of "flavors."  I've had lemon, which is fine.  Vodka doesn't have much of a taste, on it's own.  So, that might work.

Have a great dinner!


(*) This is considered to be poor sportsmanship, on your part.  If you have a great recipe for pork tenderloin .. you share!