Wendell, You will find that out of the box the locos run very well and for the price you really cant beat. The curves on your RR as long as they are at least 6’ Diameter you are OK. The 3% grade will be a rough one to overcome, you may need to adjust it a little to get down or use RC which I can help with. There is no commercial RTR rolling stock in 7/8ths yet, my first RTR rolling stock is a batch of side tipper and skip wagons but those are more geared to the UK industrial type. You can build some kits from what I offer as there are a few that will look good behind and are small 2 axle cars, OR you can take a shot at building some larger cars. Either route I have the needed wheels to build also.
Most US 2’ gauge was in Maine but there was other 2’ stuff throughout the US also, mostly not as well known except the Gilpin and the Mt Gretna. For building a larger car with trucks I have truck kits available, the compact archbar is your best bet for smaller type cars to match the Emma. Can get away building a small 18’-20’ car with these trucks and look good. It depends on what your interest is though. Eric is straight up Maine only so you wont see anything small, just look at the coaches, remember these get real long real fast in scale, upwards of 40"+
If your serious about an Emma or even just have questions, PM me or see the website they are available and I’ll take care of ya.