Booting Linux with the TrueOS boot loader?

[. .]

I'm a Linux user and have zero interest in starting a Linux/BSD war.  
But I like to test distributions and am interested in seeing how the 
other side lives.

I successfully installed TrueOS but was disappointed no option existed 
to skip installing a boot loader.  It seems all distributions should 
have that option and that's a strike against TrueOS.  However, I thought 
I could fairly easily boot to my primary Linux partition, reinstall grub 
to the mbr, and add TrueOS to my grub.cfg.

Unfortunately, I've been unable to boot to Linux using the BSD boot 
loader.  Has anyone done so?  If so, how?