The Denver Post and Associated PressVisitors to Rocky Mountain National Park could face a 50 percent increase in annual and weekly entrance fees, under a proposal aimed at helping parks across the country repair trails, roads and visitor amenities. Some members of Congress and others are expressing concerns about the proposed fee hikes, which the National Park Service says are needed to help cover part of the $11.5 billion it estimates is needed for repairs and maintenance. In May, the National Park Service will determine whether Rocky Mountain National Park will boost its annual pass from $40 to $50 and eventually to $60 by 2017, parks spokeswoman Kyle Patterson said Wednesday. The last annual pass pay hike happened in 2009,