This is an extremely large commitment you're getting yourself into. Think about how much time goes into the making of real time strategy games. Starcraft II was 11 years in the making before it was released, by a very large team of developers.
I would honestly suggest first playing around with either the Age of Empires, Starcraft, Warcraft III, or Starcraft II map editors. There are very high levels of customization in some of these, to the point that you can create your own units, buildings, abilities, and races, etc. Play around with this and see how in-depth it is and what you're getting yourself into before you make your decision if you want to try making a game like that from scratch. I don't think a real time strategy game is doable by a single person, and I don't think there is a program that suffices for it either. However, the map editors might be sufficient for what you're looking for, I myself have had a lot of fun with both the Starcraft and Warcraft III map editors.
This post has been edited by LostSamurai: May 17 2012, 02:49 PM
Oh dear... it seems I may have one more project left in me before I retire... more info soon.
The fundamental elements of an RTS can be scripted in a couple months if you know what you're doing and if you have free time. Maybe even in a couple weeks if you spend all your time on it.
Unlike starcraft 2, this isn't 3D, so there's a lot of things you don't need to worry about. I doubt most 3D RTS games in general require upwards a decade.
Pixel movement and pixel collision is already provided for most engines. You can take an ABS system, look at how it works, and then change it up to use a completely event-based interaction between events and a "game cursor"
For example, in XP someone wrote fire emblem engine. When I think RTS I can imagine if you just turned fire emlbem into real-time battle, then you pretty much have an RTS.
Of course, you'll have to add all those buildings and stuff, but a lot of the work seems to have been done already.
This post has been edited by Tsukihime: May 21 2012, 02:45 PM