Many remote locations need to be reached at least once (afterwards you will be able to use fast travel option). The length of the campaign is also greatly influenced by the fact that you have to visit distant corners of the game world. If you want to defeat such enemies without any problems then you need to have a well-developed character. This is due to the fact that strong opponents appear in further quests. Despite that, don't rush it and take your time while you progress in the game. Skyrim doesn't have a lot of main quests. It should take you about 30 hours to complete the main Skyrim storyline.
