5dmkIII long exposure/noise question

I made a first attempt at star trails the other night.
I had to limit the exposure to about 65 minutes - but enough to experiment with.

Shot info:

used 24/2.8 at 2.8, ISO 100 with mirror lockup, long exposure noise reduction on (may be an issue), RAW, SOC.

It's not a great pic, but examining the hill/trees revealed scads of color dots/noise. I don't think they are hot pixels, of which there are indeed a few elsewhere in the image, but maybe they are. Is this to be expected from very long exposures, is it possible to avoid such artifacts with better technique (and if so how?).

I've made shorter long exposures that have worked well (ie 30 sec, example below).

first is full pic, second is crop

third shows expected amounts of luminance noise (f11, 20 sec, ISO 100, SOC - converted from SOC RAW w/no adjustments using LR4)
4th is 100% crop

Generally speaking, however, I find the camera to be very unforgiving in terms of exposure/noise. Even at base ISO/ISO 200, decently exposed, noise is apparent in any area of even tones/textures that is at all in shadow - especially skin, building walls. Skies too. If underexposed at all - the penalty is stiff! It's easily cleaned up, but it's another step in PP. And ETTR can be such a bother to have to do all of the time. I have to admit to peeping at 200% - but that's because programs like Topaz DeNosie encourage it!

Thanks for thoughts and suggestions,

Jasper

--
'There is no un-suck filter.'

• David duChemin

Which is too bad, because I could sure use one.
http://www.flickr.com/photos/jasper_rubin/