A few questions:
1) Portland, OR? And what is your final destination?
2) You ever taken a mountain flying course? Are you looking to go between, or as far over as possible?
I think the best "tool" for planning this sort of stuff is a sectional and a brain.
Skyvector is nice for plotting courses between airports and navaids, but your pencil will work better for the details where you might be weaving back and forth.
Taking the route you described above, you'll be flying along part of a route I took through there (I landed at KAJZ). I have taken mountain course and wanted the "between" route. Here's what I did (in a normally aspirated 182). I'm not necessarily suggesting this as a good route, but I was able to do the whole thing at 13,500:
From KAJZ, I flew a true course of about 070, passing a little north of 7V2. I hung a left at the Paorila (sp? hard to read on the chart) reservoir, the skinny north-south one and followed the river and road to the pass that's right under V361. Went through there, headed north some more, rounded the corner and took a right towards Aspen. Flew right over Aspen and continued following the road that leaves Aspen to the southeast, through Independence Pass and on to Twin Lakes (that Mount Elbert on the left just before you get to Twin Lakes is the highest of the Rocky mountains, and second-highest peak in the ConUS). I landed at KLXV just to say I had, flew northeast through Mosquito Pass, and north to the Dillon reservoir where I followed US 6 east and went over Loveland Pass before following I-70 the rest of the way into the Denver area.
While you can do that route at 13,500, it's a bit circuitous and does absolutely nothing to avoid the big rocks. What can I say, I was sightseeing.
However, I like your route to Crested Butte and would suggest maybe even continuing roughly on that heading down toward 04V and then turning north in that big valley - Kinda the long way around, but you could probably stay even lower.
Have fun!