Yeah, save/load, and from my observation after plying it long enough, if you go all in on red/black all the time chances of winning are somewhere between 40-50%. Spider's nest has lower chances than Queen of hearts with high/low from what I've observed, and save/load there isn't possible. It's a cheesy tactic I admit, so if you want you can adjust it (for example limit how much you can earn from there per day/in total).Is it just a save/reload tactic, or are the odds really good? I don't remember it being overly generous, but it's been a long time since I added the gambling at the QoH.
Maybe having a Janet/Karen (Golden Leaf's blacksmith) deal could be one extra small quest to also offer something unique.
Are there multiple buildings in disrepair after the fixes? The one at the docks is intentional (although I can't remember if I planned an event of some sorts for it), but I don't remember others being in a poor state if you really fix everything. There are, however, the mill and the tavern which only get repairs done if the town's prosperity reaches a certain treshold (so they might take some extra effort before you can see them without cracks).
Janet and Karen coop would work since Karen is a blacksmith, but currently she only sells armor at lower prices so adding something for her would be nice too.
Ah I didn't know that those in the docks are intentional, I even thought it was a bug since you get repair the city option from Keiko's list, but the dock is still in a pretty bad state. As for other houses, there are still some weeds growing on them, so I thought that would be solved after repairing the city (also intentional or am looking too much into this?). Well, quest list says that Golden Leaf quest is still incomplete, so if you want to add something related to that you can.