we took 2 weeks back in the 80s and did rocky mtn, grand teton and yellowstone. we car-camped (tent) and did long daily hikes (no backpacking). scenery and wildlife were just outstanding. forget the exact dates but believe it was mid-summer. definitely still snow at the tops. when i was down in colo springs on business i did the train up to pikes peak, wasn't all that big of a deal. lots of driving involved, but i'd suggest you go north from rmnp if you can. side story - we arrived very late in the day at rmnp, they wouldn't let us in as the campsites were full. the ranger pointed us to a place a few miles outside of the park where we could just head up a road and camp in the woods at the end of the road. we awoke to super brite blue skies and snow-capped peaks all around, very beautiful.