Hi Ruth
It is a nice course, 2nd half nicer than the first in my view.. I did it last year and weather was lovely, mid 60sF or thereabouts. It's not flat by any means but nothing very steep, apart from a very short bit just outside the Retiro after about 40km
The incline at the end lasts about 4 miles in all - nicely done course planners! One tip - it was clearly stated in the instructions, but I somehow didn't realise that the bag drop is in Retiro (the park where the finish is), which is a good mile or more from the start.. so give yourself plenty of time to drop your bag off. Made for a good warmup for me, running from the start to bag drop and back again!
I stayed in an NH somewhere near the start, they are usually pretty reliable.
Good luck!