If you install construct classic you can open the cap file and look at the events. It should look much like c2 events so you usually can copy everything over. I don't have access to either software right now so I'm unable to do it or even see what I did.
On the other hand this is a pretty old solution and you'd probably get better solutions by posting in the c2 section of the forum instead. There's a lot of creative c2 users that may just not read topics in the construction classic section.