If we are flying in to DC and renting a car what is the best way to access the museum? Is here parking available ?

Street parking is available

Yes parking is available. Plentiful! If unable to pay for parking, train stations are near.

Yes and no there are parking garage all over city do you have tickets for museum from on line none at door

Federal Center metro stop is right at the corner, parking is close by in the lenfant parking garages or along the street is metered.

Take the Metro train. You will get to explore DC.

There are many nearby parking garages that you can use, the nearest is $11/hour or 21/day, and there are a few hotels within walking distance of the Museum if you're staying in one.

Parking is on street but fee garages are very close. Or take Uber from your hotel.