@jeremykeller : Apologies for the late answer. Christmas traditions in my family are quite time consuming. Climbing ladders etc. is something I’ve wanted to add for a long time, but I’'ve indeed been limited by a lack of animations. I will be adding it at some point, with some horrible placeholder animations probably, but I’ve prioritized other features first. For telling the GridManager that a ladder connects two tiles you can use the AddEdgeBothWays function in BP_GridManager with the two tile indexes as input. This will allow you to move between them. After this all that remains is animation.
Animating movement in the base toolkit is pretty basic, with a walk/run BlendSpace driven by a float variable which also controls movement speed. For changing this animation to be determined by various obstacles in the way you would have to be a bit creative, and though I’m sure there are many ways to do this, animation is not something I’ve worked that much with, so you might be better off asking in the animation subreddit, but I’ll give you some ideas to get started.
You would start at the AccelerateAndMoveUnitAlongSpline function in BP_Unit. You would want to add some branches/switches so that you can prevent the default animation and movement along the spine from triggering if needed. For detecting that you should transition to a climbing animation you could possibly use collision boxes attached to your ladder actors. If overlapping you would switch to a climbing animation and maybe follow a custom spline component contained in the ladder actor before switching back to the regular movement spline at the end of the ladder spline.
Something like that is at least one of the first things I would try if I were to experiment with this myself. Just allowing a unit to move between the tiles on the top/bottom of a ladder is very easy, but animating it so it looks good takes more work.