TINPLATE

I think it is foolish to narrow it down to one vendor - inventory of tinplate can be had in any hall. Presuming you are toying with an "attack plan", I'm not sure there is a best place to start, but would suggest the member halls first as the orange hall typically has extended hours. Cover as much ground as you can as fast as you can and if something catches your eye, get it then and there, don't even consider the possibility of revisiting because it won't be there when you go back.

In the Orange Hall--and for newer tinplate--be sure to stop by Sidetrack Hobbies (if they are there). I have bought a good number of O gauge tinplate items from them over the years.

Jack Rash, normally near the SE corner of orange, usually has a decent selection of repro tinplate.

To follow on to what Allan said about Sidetrack, as I recall they will discount to cover the tax if you are paying with cash.  This is a common practice by many dealers - it pays to ask - if they don't cover the tax, write a check or use a credit card and save your cash for use elsewhere.

See Josh Rosenberg in Blue Hall, he'll have lots of vintage standard gauge. Usually a fair amount in Orange, including Prendeville and a couple of other dealers how sell high end originals. There was a guy at the left side back of Orange that had a smattering of open box MTH standard, not sure if that has dried up.

And in the member halls, stuff can turn up at any turn. Couple of buddies of mine usually set up in Red Hall, somewhere towards the middle/front.

And make sure to visit our SGMA 30 by 50 foot layout on the right back of Orange Hall, where Atlas used to be, near Lionel.

All bets may be off this time with the wider aisles, some folks may be in different halls.

Jim