I've been wondering these same questions for a while as well (as I'm sure many others are too). I spoke with a fellow at Firehawk about the details of his entrance into the fire world and he said he was basically in the right place at the right time. Unfortunately, this industry seems to need personal connections more than anything else and you just need to network your way into a position. This particular fellow had no previous fire experience and they more or less allowed him to ride along to gain some hours.
I spoke with Matt Zuccaro about this particular aspect of the fire industry about a year ago and he echoed my frustration. It seems the only way to get fire experience is to fly with a fire company (duh), but the only way to get hired on at these companies is to have fire experience. So unless you have an inside scoop I can't seem to figure out a way to crack into it. Matt suggested that the industry and the FAA were coming up with some sort of "accredited" fire school to get the requisite experience but I haven't heard of anything along these lines actually coming to fruition.
As far as mountain time goes, the FAA has designated certain parts of the US (and world) as officially mountainous which can be logged as such. There is a convenient chart in the AIM (Figure 5-6-2 as of 2009 edition).
Best of luck.