Hi Patrick,
wow, that looks great. This is what we all wish for when we think of a sunset… the sky is burning, nice dramatic clouds… and most importantly, you managed to get a nice composition. The snow-covered mountain is beautifully framed by the coniferous trees. The picture makes you want to stand there and enjoy the sunset.
If I see unplanned such clouds at sunset, then I usually do not have the camera with me or am in the middle of the city. 
Great that you endured the mosquitoes. It was definitely worth it.
Was the dynamic range really too large for only one exposure to be sufficient?
The Sky selection in PS isn’t perfect. After creating the selection you could use the Select and Mask feature to further improve the selection. But sometimes it is not possible to avoid halos and you have to remove them afterwards. Here on NPN is a link to a YouTube Video that provides a simple workflow to get rid of halos.
I downloaded your image and played around with it. Here is my result:
- I tried to fix the halos in the center of the image using the Clone Stamp tool.
- I reduced the saturation in the cyans. Thus, the green tones under the trees on the left and the mountain in the background no longer attract so much attention.
- I dodged and burned here and there to equalize the brightness of the mountains a bit
I quite like your crop. As an alternative, you could try something like 16:9:
BTW, I just did a quick research about the art festival. That looks like a lot of fun. Did you exhibit your images there?