Given the distance and reasonable time needed for travel, we'd also suggest you choose either RMNP or YNP/GTNP.
ALL of these parks are at a high elevation, much of the area is over 8000'.
We are active but find that it takes a day for our bodies to adjust to the increased elevation and have our normal level of stamina.
You will find your two weeks will be full with great hikes and sights to see.
Looking at the park maps, YNP and RMNP are not small parks. It takes more time than you would think to get anywhere, during the height of the season.
