I reckon you can basically do anything you, imagination is the limit sometimes, well not always sometimes FSX has some slowdown points.
To keep it interesting I use it to get to know different aeroplanes, from heavy metal jets to light fabric aeroplanes. A VC is mandatory for me as is REX Weather.
I like to explore the FSX world, and there are always surprises in store for different airports around the world, designers little touches and special finds like that. I am also member of a VA and do a bit of hauling in the DC-3 with them but flexibly.
I find the sim a really great way to explore the history of aeroplanes and different eras so you add to your knowledge of some types and enjoy flying them, some of course, the slow ones your glad to move on from.
My recent bit of fun was to use the GPS and Dead Reckoning nav to take the KBT P-3 down to Macquarie Island in the Southern Ocean departing from Hobart then back to Invercargill on New Zealand's south island, yep it was there and pretty much like the real thing, had great fun and that was a long overwater flight with little inbetween.
Before such flights or flying in different countries I will add to my scenery library and improve stuff as much as I can either freeware or payware and generally improve the experience. My favourite places at the moment -Australia, Japan, Pacific Region and now New Zealand. Sure is a lot of the world to explore. Maybe South America next.