There are lots of preservatives available that will work to prevent rust; but it's wise to choose one that's a good match for your particular weather. Yes, at the top is Rig grease, but I consider it more as a "stored-away" preservative in the same class as cosmoline. My guns rarely go more than a few weeks without me checking/tinkering and doing maintenance on them, so my choices might not be sufficient for your needs.
My take is somewhat controversial. I've used WD40, 3-1 oil, several gun oils, etc in the past with excellent results. But for quite a few years I've settled on Barricade or BreakFree CLP for use in the bore. I occasionally wax the stock but I always wipe the lock, stock and barrel with a cloth dampened with TYPE F Tranny fluid. Type F is very waxy and protects the stock finish and all exterior metal. I've been using it for 20 years and it keeps the wood AND metal protected.