Ran across some images and videos of a model I loved growing up called the Starcruiser 1 by Airfix. It was cool because it was more of a toy than a model and it separated into four different vehicles (this was before Transformers and that ilk). My understanding is that it was the creation of Gerry Anderson (Space 1999, Thunderbirds, etc. designs). So I figured I would create something new inspired by the original and I came up with the Starcruiser 1 Refit 2019. It includes four pieces that can be joined into one larger craft. I think I handled the tolerances and connections pretty well, but I haven't printed it yet so it may change once I get to that point.
Still using Tinkercad, though I do have Fusion 360 and have played with it a little, just need to take the time to properly learn its in and outs.
Did borrow some bits and pieces from other thingiverse creators for it, but the majority of it is my design using tinkercad basic shapes and advanced shape generators. See Remix list for attribution for the parts I incorporated.