Echoing some of the above
.
Either resort is a great place to spectate. I agree that you get a great two-fer by walking over to the TTC. You can walk from the GF to the TTC or monorail. Just make sure you stay on the lake side of the course and do not cross over to the kennel side by mistake. A great thing for the TTC is to come forward along to course towards the roadway. My DW has a knack of finding a corner in the course and she camps out there. Then its a short quarter mile walk back to the Poly. The intersection of Floridian (the road in front of the resorts) and Seven Seas is where the course opens up.
Just be aware that the marathon has started to orange fence the spectators from the course from the GF through the above intersection. There is a stretch between the resorts that is not fenced, but it is also heavily landscaped. Security has on occasion prevented folks from going too far past (south) of Seven Seas and along the MK parking lot.
As far as chalking, there is very little of that. Frankly, I am surprised there is as much as there is. The roadway is open to heavy traffic pre-race and then once closed off, security tends to not let guests play in the street.
Sharpie, an official sponsor of the event has a sign booth. With a little creativity you can knock out signs that are very bold and easily spotted. I would bring along my own supply of material to be able to work on your sign in the room.
DW has a way of enlisting folks into a huge cheer squad. Seems like spectators are looking for someone they know to yell for. So by creating these temporary squads, it seems to enable these new found friends to yell for each others runners.