Created the same pieces you were working on as well as other variations of stretched and transition pieces. Also created a dedicated downhill water piece, renamed the collection to meet with my new standards, and designed 2 larger curves for paths. I will upload them some time this week I'm sure. Here's a screenshot.
To be honest, this pack has gotten more complicated to use than it was originally intended. I think it will be ok once Assetforge allows grouping, but I may end up bringing this pack back to my original idea of an outdoor puzzle level pack that uses a noticeable grid-based format.
I see Assetforge as an amazing tool, but not meant for nature. Unity and Unreal both have built-in tools meant for that.