mounting an ubuntu 14.04 bhyve image as a filesystem for editing

[tech-lists]

Hello list,

[originally sent to virtualization@ but got no replies, probably 
because, thinking about it, the fact that it's a bhyve image is incidental]

[snipped stuff about bhyve]

Is there a way of taking an ubuntu VM image that normally runs as a 
bhyve guest, mounting it on some mountpoint on the freebsd host and 
directly editing the files within it?

Alternatively, is there a way of making grub boot the image into 
single-user-mode like one can with freebsd?

Many thanks,

-- 
J.