I just got back from 3+ weeks on my belated honeymoon too (that's what happens when you marry a teacher)...it's a lot of work catching up on all these threads.
Congrats! And yeah, it's quite a task getting caught up, haha.
Regarding Tim's at stations: I think the point about peak vs off-peak traffic is a valid one. IMO, to start off with, they should only be located at stations with AD2W service OR stations that are a major intermodal hub. Stations that come to mind are: Aldershot, Burlington, Oakville, Port Credit, Pickering, Oshawa, Milton, Bramalea, Brampton, Unionville, Langstaff, Newmarket.
The reason I chose those stations is because they're either busy AD2W stations, or they're major GO Bus transfer stations, which usually involves a bit of a wait. Some of them are both.
Regarding Presto payment: I still think the best option is to go with an App + ApplePay/GooglePay or whatever. Have the app be the front end UI with payment and system info, and let Apple or Google handle the back end payment. You can even go 1 step further and install iBeacons in every station or on every bus/streetcar, that can tell when that phone got on and off the vehicle, and charge them an as-the-crow-flies distance based fare.