can someone offer advice?

Here is my scenario.
Several of the small General Aviation airports i frequently visit in real life are robust GA hubs with a lot of wonderful activity and unique scenery.
specifically some of the grass strips!
unfortunately, many of the ones i visit in FSX / FS2004 are little more than a green strip of land... no hangars, no parked airplanes etc.
because there is so much that needs to be done to a few specific airports of interest to myself (and probably very few other people), i would like to get into scenery design on my own.
the only question is... where do i begin?
is there a program that will allow me to take the default scenery for a grass strip and add a parking area, and perhaps some parked J3 cubs and a hangar or two?
any help would be great?
Several of the small General Aviation airports i frequently visit in real life are robust GA hubs with a lot of wonderful activity and unique scenery.
specifically some of the grass strips!
unfortunately, many of the ones i visit in FSX / FS2004 are little more than a green strip of land... no hangars, no parked airplanes etc.
because there is so much that needs to be done to a few specific airports of interest to myself (and probably very few other people), i would like to get into scenery design on my own.
the only question is... where do i begin?
is there a program that will allow me to take the default scenery for a grass strip and add a parking area, and perhaps some parked J3 cubs and a hangar or two?
any help would be great?