So, the problem in the first few miles is not a lack of trails to follow. You will be traveling for 2-3 miles through Newcomb Park. But the trail does not really follow Newcomb Creek. So, the problem is attempting to figure out which trail to follow. Because there are no signs in this section. But, there are a lot of cow trails going everywhere. So, just a friendly word of warning. Keep looking at where you are going. If you don't eventually see some slash marks on the trees, or the trail dug into the side of a hill really deep (like it's been used for 50-100 years), then it could be you are not on the trail you want to be on. That said, the main park does mostly follow the trail, so if you just keep heading up the park/creek, you will see where the trail crosses Newcomb Creek and begins to gain altitude.
As an example. Another meadow to cross and one trail goes left and another goes sorta straight. Hmmmmm. The one that heads left is hard to see since it's in the shade, but it is the deeper of the two. However, I think the one that heads to the right (and up into the aspens) is the correct trail. But, I think they both (or, all : ) come together up where the aspens meet those beetle killed pines (cows have a tendency to make a lot of trails). All the aspens in this park must look pretty nice come fall.