I think going a few years into the past would be pretty amazing. Though definitely not as practical, I can see this roleplay set in the early 20th century, with biplanes and mother-base esque airships taking to the skies; besides this, the early 20th century is also widely regarded as the last grand era of exploration. 

Ships of the era were finally powered by a steam, a grand advancement that allowed for the world of exploration and seafaring travel to explode like never before; such would be, in my opinion, rather intriguing to see.