I flew 2004 for years and really enjoyed it. I've had FSX for a year and half and love it.
But, I've only really played around with them, all of these years. Flying warbirds, landing on carriers, crashing helicopters, and trying to make Hiedi scream in the Piper Cub.
I'm taking a real life flight from my home airport, Northwest Regional in Roanoke Texas (52F), to Clark airport, in Stephenville (SEP), tomorrow.
Thought I'd run it in FSX, just for some fun. I fly a Cessna 172S with the Garmin G1000 nav system, and luckily FSX has one. So I planned my trip just as if I were going, and jumped in the 172.
Should do it more often, cause that was fun. Followed the route on my sectional and my G1000 moving map, and everything matched perfectly. All landmarks were there and all the airports I was supposed to pass along the way. Right on schedule, there was SEP up ahead.
Unfortunately, FSX's Clark airport is not as detailed as the beautiful (and free) rendition of 52F that I downloaded from simviation. I didn't see the restaurant that's there which has some killer barbeque!
If you enjoy the sim, and even if you aren't a real pilot, go and buy yourself a sectional map of your area and take a flight somewhere. Lotta fun

Recreating real life flights is something I've tried to do for each one! I rarely use The GPS or even the map much, unless I need a frequency for a beacon/vor... Yep, doing approaches in zero vis storm weather with only old-school beacons, vor's and ILS, with an older classic plane, that's what I enjoy these days.

I've flown (as passenger) my share in Austria, mostly Helicopters, and it is indeed no problem to recreate these flights in FS with any kind of good scenery. What I like a lot about this is that it gives you a very good feeling of landmark relations and directions for your country. I know Austria better today than 3 years ago, and I would find my way around in some areas without ever having been there.

An additional tool for "virtual preflighting" is Google Earth - you can actually find your landmarks there, put them in an FSX flightplan and then fly.

I am not a real flyer unfortuatly but yes I sometimes do like to fly by the rules and I found it best for me when using Photoscenery of the UK so I could fly from my hometown local of Humberside to Duxford flying around the no fly zone of waddington/lincoln to avod red arrow practices.

Was great fun esp when I did it online with a small group of MP players 'humberside flyers' with ATC on and having to tune the radio to pick up comms etc it all added to the immersion, tuning to 118.55 on power on to make first contact etc, great stuff.