Before doing any of this see the Dosbox section below to consider downloading an updated version of dosbox!



All you need to do to add this string is find your Blood dosbox config, to do this:
Go to Blood in Steam
Right click and choose properties
Go to browse local files

Next open your 'dosbox.conf' or 'dosboxBlood.conf' with a text editor like notepad and scroll to '[autoexec]'
go below the last line of that section and copy the following lines in:

String with map maker option (add to [autoexec]):
http://pastebin.com/qfYmqwAK
http://pastebin.com/FJg8xRgG

My dosbox config: (just rename .txt to .conf and backup your original)
{LINK REMOVED}https://www.mediafire.com/?r5kay5lmkv2c5p2

Improved networking string by Oberschutze♥♥:
http://pastebin.com/h0regLqm

The result should be the following prompt upon startup:

The Steam version of Blood gives you version .73 of the main dosbox build, not only is this version out of date, it ignores the many SVN builds available.

Including a different version of Dosbox should be as simple as drag and drop

I highly recommend Taewoong's SVN build, among its many new features it includes an optional menu bar like many popular emulators for modifying many settings without opening the config.
http://ykhwong.x-y.net/

To Update the Official Build:
http://www.dosbox.com/download.php?main=1

For a list of other svn builds:
http://www.dosbox.com/wiki/SVN_Builds