The Bucegi Mountains are one of the top vacation destinations for Romanians. Do as the locals do. For trekking and cross country skiing, they’re as good as it gets, with an excellent, well-marked network of trails (some which can be biked). For those over-nighting, many cabanas are open year-round.
This site has detailed information on hiking trails around Bucegi.
Weather can be an issue, no matter when you go. When year-round winds can be astonishing and winter even worse. Moreover, avalanches close wild skiing options during the spring thaw and summer thunderstorms are common. The lifts close when the wind gets too fierce.
Crowds in summer can make the cable-car rides up from Busteni and Sinaia a day-trip in and of itself after the wait in line (up to two hours!).
Try to get the hiking map made by Hungarian Dimap; it’s a fold-out map “Five Mountains of the Carpathian’s Bend” (Piatra Craiului, Bucegi, Postavarul, Piatra Mare and Ciucas, plus a Brasov city map).
For some pics of the area, go here.
A few cabanas in the area have put up web sites. Some are only in Romanian (for now).
The pictures above were taken and generously provided by Iulian Cozma.