Scotland is great, you guys could stay in some really cheap accommodation, like airbnb can be really cheap with some places charging very reasonable prices for a week or two,
While you are here you could explore Glasgow as we have a big city centre with lots to do, lots of history, museums and art galleries, i’d recommend the Kelvingrove art gallery, the Science centre, the transport museum, also Stirling Castle, Edinburgh Castle, and there are lots of other interesting and unique Castles and heritage centres, also the zoo, you can hire bikes at various locations as well like train stations and bus stops.
The scenery is amazing as well, you could even go camping if you couldn’t afford a room, i’d recommend camping on Loch Lomond, maybe hire a car.
But yeah the sz convention would be an event, maybe meet over the course of a few days on international mental health week or something, we could have stories of recovery, poetry readings, art exhibitions or a crafts fare, brain training, hobbies and ideas of interests, virtual reality testing, youtube presentations, stats, awareness, stigma busters.