What is the fine-grained topic of the following text: Towards the end of April- early May (date depends on weather) I will be embarking on a pretty big challenge and carrying a full sheet of 8ft x 4ft, 3/4" thick ply 4 1/2 miles up the Llanberis path to the top of Mount Snowdon wearing a 20kg weight vest. Only return the topic.
Carrying a large plywood sheet up Mount Snowdon