I think pavers will be the easy to maintain.

First, I'm floored at the size of your mulberry tree! That is just super cool! I think pavers are great per the previous suggestion. You might also consider just doing a gravel (maybe crushed granite) walkway with pavers/blocks along each side to keep your gravel in the pathway.

I'm still in awe at that tree and I'll show you why. I'm a wood turner...make bowls and such from trees that have died or blew down. Please take good care of your tree but if it ever looses major limbs or dies, please try to contact a local wood worker club to make use of the wood. It's some of the most beautiful native wood I have worked with.

Agree with lisedv.Largish pavers as illustrated will coordinate nicely with the house,and will be easy to swap out if one cracks.
Keeping a slight curve to the path will also add an eye pleasing welcome vibe.Nice house,magnificent tree.

Doesn't the mulberry tree leave blackish marks all over your sidewalk, etc? We have one near next to barn and it is insane how many berries we have that drop everywhere and stain the cement. It's an awesome tree but not for an entry. Do some sort of dark stone or winding black top path with beautiful flowers lining both sides if you keep the messy tree.

Or you could have the walkway come from the side sidewalk and avoid the berry mess altogether.