Saving 80,000 Gold in Another World for my Retirement 1 (light novel)

Mitsuha is your average teenage orphan—until one day she falls off a cliff, and finds herself in another world strangely akin to medieval Europe! Beset by wolves, she discovers she has the ability to travel freely between the two worlds, and decides to make a life for herself in both. Now all she needs to do is save up 80,000 gold coins for a comfortable retirement... Piece of cake, right?! 

No matter how out of control things get, Mitsuha keeps her cool, turning every hurdle into a business opportunity. From shopkeeper to war hero to viscountess, her meteoric rise seems unstoppable—but with each success comes new obligations and new costs. Does every step up just take her further from her goal??