As a long-time Trek fan who just finished watching the ENT series for the first time, I realized that there were very few clues on just how large and widespread the Vulcan state[1] actually was, compared to United Earth.

On one hand, they have been warp-capable for many centuries and should have had the opportunity to reach much of the Alpha Quadrant before many of the rivaling spacefaring empires in the region. For example, Carbon Creek indicates that they had already been aware of Earth for some time in the 1950s. This seems to provide good reason to assume that the Vulcans could have had a pretty large territory by the 2150s. Though an aggressive colonization policy does not seem very likely, not putting all of your eggs in one basket does sound like the logical thing to do, don't you think?

On the other hand, we know Vulcans don't go particularly out of their way to explore unknown regions. I'm not certain if that attitude also applies to colonization and terraforming (vulcaforming?). The Vulcans have a border with the Andorian Empire, and in Cease Fire, the planet Paan Mokahr/Weytahn was described as being on that border, but also as being very close to Vulcan, the home world (T'Pol even compares it to Pluto - implying it's in the Vulcan home system!). This confuses me a lot, how can the Vulcans not have managed to secure their own home system in the past 1500 years? Did they expand but lose lots of territory to the Andorians and Romulans or other more aggressive species?

So, to get to the point, does anyone have (semi-)canonical information that can give me some idea about the extent of the Vulcan state? And as a fairly related question, just how expansionistic are they?

[1] Call it what you will, Confederacy of Vulcan, Planetary Confederation of 40 Eridani, Confederacy of Surak... See here for a discussion on its name. 'Vulcan state' seems neutral to me.