Advice on finding parking for Boston Pride?

Disclaimer: Please please answer the question as such; I don't want answers of "don't drive" or "don't go."

I have a chronic illness and am hoping to go to Pride. I LOVE Pride and don't want my illness to take this from me! I can handle an outdoor crowd for a while but when I get too overstimulated, all my symptoms flare badly. I need the ability to leave quietly and easily at any time, hence taking my car. A long multi-line T ride or a struggle to find an Uber in a crowd once I'm already cooked might take literal days to recover from.

I know it's a bit crazy to even contemplate parking at such a huge event, so am hoping folks who have driven there before can offer advice. Where would be some good places to look for parking that you can get out of mid-event (not on the parade route) and available for more than 2 hours? Some walking between the event and the parking spot will be fine.

On a related note, have any of you taken breaks in the quiet/sensory tent at Pride? How is it?

Edit for clarity: I do NOT have a disability placard.

Edit2: SpotHero is glorious. Thanks for the idea and helping me figure out the area to look in. I'm way less stressed about it now. Happy Pride! 🏳️‍🌈