1. MLKing Drive, aka West River Drive, is closed to auto traffic from 8 am till 5 during DST, so you can't drive there anyhow.

2. There's free parking below the west side of the Museum. Turn from Kelly Drive, aka East River Drive, onto Waterworks drive. Take the path past the Waterworks to MLKing Drive and walk across the bridge till you're opposite the boathouses.

3. Despite #1 above, after noon you can drive out MLKing for about a mile. You will pass a pull-out just opposite the boathouses (there is a fish ladder there) where you can stop for a minute or so.

4. After 5 pm you can drive on MLKing and there's plenty of free parking. Park in the lot closest to the museum and walk down to the boathouses.

There's paid parking on the west side at the Zoo at 34th and Girard. If you then walk to the riverbank, it might be a bit too far north to see the boathouses. There's also parking further south at Amtrak's 30th St Station, but the absolutely best bet would be to actually park in the Art Museum area. Just my recollection...but if you check the local transportation company, septa.org, there is at least one bus that goes to the Museum area and is accessible from center city where there are many more parking opportunities. Take lots of beautiful pics. It's supposed to be really nice out today. :-)