Is this fairgrounds metro accessible?

start date

Metro bus and Ride On.

By bus mostly

Not directly from the Shady Grove metro stop, you'd need to Uber or bus to fairgrounds

Yes

Yes, get off at Shady Grove take a Ride On Bus heading north. Check bus number on Ride On map.

You get off at the Montgomery Village Mall and catch the shuttle

Not that I know of but it's a nice place to meet people and have a good time at the flea market there some Great there's a great person there