There are two campgrounds ON the Sun Road near the east entrance. St Mary is one and Rising Sun is the other. There are several OTHER campgrounds on the east side of the park but NOT on the Sun Road. These include "Many Glacier" and "Two Dog" campgrounds. Many Glacier is about 30 miles NORTH of the east entrance and Two Dow is South of the east entrance and accessed from the town of East Glacier. You WILL not want to drive your RV across the pass on the Sun Road EVEN if they didn't catch you trying it :) Standard pick up trucks cannot pass in many areas with tow mirrors extended. Fortunately (due to a lot of stupidity) it IS possible to pass someone with THEIR mirrors extended as long as yours are not.