I agree, Andrea.
There may be a lot of reasons involved here... First, I think they were able to get an early start. Hwy 140 is heavily traveled so probably somebody noticed the fire relatively early. Hwy 140 and the residential roads coming off of it give relatively easy access to the fire (as opposed to say a lightning strike in the middle of wilderness). There are at least two fire stations in the (broad) area, so that also probably helped give them a jump on the fire.
Then there are the incentives to squash it quickly: Proximity to the county seat (Mariposa) and the population cluster there is one reason. Then there's the close proximity to Yosemite - they're going to make every effort there, both for the park itself, and also all the tourism-related things (motels/inns/hotels/campgrounds/etc) that are spread out all over the area to the south of the park.
I'd be deliriously happy if this (and the one threatening the sequoias) were the only CA fires this summer, but October and possible rain is a long way off.