This might sound lazy but...
Is it possible to write down all of the game rules in a .txt and load them?
I mean for example instead of typing:

You can just type something like /se seesaw.txt

If this has not been done, consider this a suggestion
If it has been done, how do you do it?

Need to use a script. Check the LUA scripts forum - Blam made a serverbot script that can set the server to preset modes, but I don't think he's released it to the public.

I was just about to drop something similar in the suggestions forum... Except I visualize it the other way around... You set the server manually, then save it as a preset, which, aside from being accessible from that point onward, gets output into a central file somewhere... In a short while, we'd have a sort of mode database. Easy accessibility of preset modes increases variety in the toribash experience, and promotes a better understanding of the TB fundamentals. (As opposed to the current situation where people are often good at one or two modes in particular, and suck at the rest)