I did a Maple Ale last year. A friend gave me 15-gallons of sap.
I boiled in my electric boil kettle, until it was about half the original volume.
I used this "sap" @1.015 in place of water for the whole process, mash and sparging.
I used a simple grain bill of;
7# of 2-row
2# of Caramel/Crystal
I used 16-oz of 100% maple syrup in the boil.
Hops, 1-oz Chinook @60
.34-oz Cluster @45
.13-oz Hallertauer @5
BeerSmith had the gravity to the fermenter at 1.055 using water. I got 1.070.
I did 7-days in the fermenter, using #WLP001, Cali Ale.
I followed with a week in the secondary.
I bottled at 1.008. (8%ABV)
The brew was quite tasty, with a definite "woody" fragrance, and slight hint of maple. Definitely not too sweet, which I thought was a good thing.
I'm hoping to score some sap this year, so that I can try another batch.
I don't think I would change anything, except to double the batch if I can get enough sap.