Hmmm, advice for starting large projects? Start off with small, realistic plans. That way you can appreciate fulfilling them. I started this fort after seeing a number of others that inspired me to try something new. At the start, my only plan of action was to do everything I normally did, just a little bigger. The very first thing I did was instead of a 3-tile wide hallway, I made a 5 tile wide hallway (the same one you see running North-South through the fort). Instead of 4x4 bedrooms, I made 5x5 bedrooms. That forced me to plan ahead to leave plenty of room for expanding, which is what allowed me to build basically everything else. But it was always (until these last few projects) just small steps at a time. Almost nothing was planned out far in advance. Not even the artificial lake. I had just left enough room so that I was able to fit it in.
Also, I never did anything I couldn't undo (within reason). All my lakes have drainage valves, same with the magma. So theoretically, I could still pull off a major overhaul if needed, which is good to know though it will never happen.
Also, it's been closer to 14 months, but 2 of those were spent with a dead laptop doing nothing. So in practice 12 months is almost exact.
BTW, any plans on uploading a save?
Eventually yes. First I want to take a break for a few days, and then decide what I'm going to do. If I continue working on it I'll probably hold off on posting a save until I get bored, and simply commit myself to doing so. It's a lot easier to post a save than collect all the screenshots from the past year which are scattered between computers and write out everything for this thread, so I think I won't have a problem doing so.
How does it feel to have created a legendary fortress?
Mostly awkward, since it was just simple fun for me to do so. But so long as other people are inspired to work on their fortresses, then I don't mind sharing it.