Marin MTB eldridge Grade
As others have mentioned you'd be cheaper getting a new bike than upgrading.  The frame also  won't support disks,  although if you replaced the fork you could fit a front disk.

Importantly the geometry of a bike has changed quite a lot since those days. I've got a marin pine mountain from around that time and it feels really unstable compared to a modern hardtail and is not corrected for a suspension fork.

However to directly answer your question I think if you replace the entire drivetrain it should work. The rear hub spacing should be 135mm.