Copy the c:\GOG Games\Little Big Adventure 2 somewhere you can access from linux, eg.:
/home/$USER/dosbox

You can also install via Wine on linux and then copy the files installed to your ~/.wine/drive_c/GOG Games/Little Big Adventure 2.

Install dosbox, eg:
"apt-get install dosbox",
"pacman -S dosbox"
or whatever

Run dosbox, execute the commands with the appropriate tweaks:
mount c "~/dosbox"
imgmount d "~/dosbox/LBA2.DAT" -t iso
c:
LBA2.exe

Have fun.
You could use the dosbox config files (dosboxLBA2{.conf,_settings.conf,_single.conf} to autoboot LBA2 but it worked well without them.

Using arch linux (updated today), with dosbox-0.74.

No idea why GOG didn't release a linux version. Perhaps licensing issues.

Thank you, it worked perfectly! I also use Arch and had tried PlayOnLinux to install this game because I read somewhere it was the best way, but to no avail.

This game is amazing, one of my favorites from my childhood, really appreciate it!