Tateyama Kurobe Alpine Route

I plan to travel on the Tateyama Kurobe Alpine Route from Toyama. Can I turn back at Daikanbo, that is not taking the ropeway? How to return from Murodo to Tateyama?

If there any easy walking route around Murodo in May?

Can I turn back at Daikanbo, that is not taking the ropeway?

Yes, you can travel along the route in any way you wish as long as you get the according tickets.

How to return from Murodo to Tateyama?

The same way you came: by bus and cablecar:
https://www.japan-guide.com/e/e7550.html

If there any easy walking route around Murodo in May?

The snow usually disappears in June. Depending on the year, some of the trails may be snow-free already a little earlier. But it is better to expect the trails to be snow-covered all through May and bring footware accordingly.