Would there be a space at Riverside mbta parking lot as late as 7.30pm on July 4th?

no lot is always full on the 4th people come and go all day but practically impossible to get a spot after say 530 6pm..

It would be extremely tough to find a spot that late. I happen to work there. I would suggest an Uber if at all possible.

Yes, it's a very big parking lot.