Caveat... I am not a real-world pilot, and my knowledge is fairly limited.
I live outside of Boulder, CO, and in FSX, I like to fly my Carenado Cherokee 180 up to spots in the high country. I usually fly out of Jeffco (KBJC). The airport is at 5673ft. In order to get to Granby, I have to gain enough altitude to get over the mountains. I fly Rollins Pass, wich is 11680ft. then on to Granby.
My question is, what would be the most realistic way to gain the altitude before heading up and over the mountains?