I think you should have a look at MAME compatiable nes emu's
There is a dos emu called rocknes and there is a mame version of it to.
What i mean is u can use a frontend to launch the game stright away and it uses the standard mame button config and all u do is hit esc and it will close down the emu.
It's made for arcade cabinets with the joysticks and buttons so no keyboard is needed.
You could make a frontend or get a mame frontend to launch the nes games
If u want more info im happy to help im at work so if u can't find the mame compatiable version of rocknes i'll get it off the home pc
I have nes snes genesis/mega drive and sms setup on my carpc for people to play with as i drive and i of course have mame 2