I am located in Arkansas and am having difficulties locating rock wool or mineral wool insulation for local purchase, without special ordering. The mass heater on the drawing board is for portable use during camping and am looking for a light material for transport.

Are you asking about insulating the heat-riser? So, alternatives to perlite and vermiculite, etc? What part of the rocket mass heater are you insulating?

I am looking to insulate the internal chimney inside the barrel. Is there a way to use adhere the vemiculite? I thought about using a flue pipe around my heat riser/chimney and filling it with vermeculite or the fiberglass insulation. Thoughts/ feedback?

I'm still not sure exactly what you're asking.

But have you seen this video?:

http://www.youtube.com/watch?feature=player_embedded&v=GkHOwmKyL7A

Within the first couple minutes, the video shows them mixing perlite and clay to insulate the heat-riser. The heat-riser is made to be portable. Also, while perlite is a rock/stone substance, it is very light-weight.

Also, this board is very informative, may be helpful for you:

http://donkey32.proboards.com/index.cgi?board=cast

I have seen that video, and had forgotten about it. I believe you hit the nail on the head. Plus the price is right. Thanks- DW