The 100k is a lot of investment. Stick to what your doing now though. There is not enough time left till prepatch to make the investment worth it if you start.
All of this on as many rooms as possible. I did this on 11. Would have done 22 since I'm on combined server... but didn't want to spend the time...
Level3 inn. Gold missions+recruit another gold hunter each week
Level3 barracks. Extra expenses missions. And 25 follower slots
Level2/3 Dwarvern Bunker. Makes gearing up your followers easier 3 helps but not required
Level1 trading post. Turn extra garrison resources into money with it.
Salvage yard level three. Spam missions of all kinds. Gives you boxes of gold. Stuff to put on Ah and tmog/gear of to sell
Makes lots of gold. But requires a lot of time/gold investment to start up. And come pre-event it will all be nerfed a ton. So don't start now. Just stick with farming cata 25h runs
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You get 250g a boss... so no "exaggerating" as then you also get hundreds of gold worth of gear... if I wasn't in bed about to sleep. I would do a run. Sell the stuff. And show you the profit