What in your opinion is a good length for an adventure map?

The one I am currently working on, which should be released Friday is likely around an hour + some. There will be two main paths the player can take (or finish both)

The map itself is custom, along with around 30 collectibles. Is that too many? Most items are found by exploring the map, but not all.

My first custom map with no buildings became more liked than I thought and I wanted to out do myself at least 100%