I drove out to State Hill Rd Marina on the south side of the lake to check out the water and see if it was good for the family on a future trip.
The access was clearly marked and easy to find. In summer it's 3 bucks per vehicle to use the area. Once down by the water there are two parking areas: one (massive) for trailers and another(adequate) for single cars. I parked in the latter and then walked my canoe and kit to the water's edge (30feet).
The water was ok. Wide open, windy and a little choppy. The water in Blue Marsh also seems to always be quite warm. It is in the basin that allows speed boats, so you have to be heads up at all times. There is little to no shade and most little nooks along the bank will be occupied by fisherman. I probably will not take my kids here until they older and stronger.
nice ramp, a few hiking trails, picnic tables, broad shore line. didn't notice facilities
$3 per vehicle
222 to Broadcasting Rd exit. Right at base of exit. Left on Tulpohocken Rd, Left on Reiger's Mill Rd. and then Right into the Marina.
I used a Road map of the area that labeled the lakes amenities very well.