Pulled the lists from my last few recaps from the Marathon thread. If you dig back further, or check some of the other race threads you can probably find some others as well. As a general rule, they won't post the lists in advance. A few times back when MarathonFoto did the pictures they did pass out 4x6 prints of the course map with the photo spots listed. If you watch threads on the various boards, you may see random rare characters do popup sets in late Dec/very early Jan, those are often training sets for the Marathon events. Or sometimes the board members that have access to the CM staffing schedules will post a few hints.
As
@LindsayLoves said, the characters will still have to do their sets and swap out. If it is a solo character, it may take them a minute or two to be replaced, so you would be standing around waiting. If there are multiples, they will usually rotate through to minimize downtime.
Most characters aren't in places the public could get to, so either in parks that aren't open, or in backstage areas. For the half there is usually something on World Drive about a 1/2 mile before the toll booths, one over by where the speedway used to be, one just before the wooded area mid parking lot, one in Tomorrowland, someone from Alice by the teacups, one or two in Fantasyland, someone popular on the castle you can't actually get a picture of other than a long range selfie, someone in Frontierland, a float or parade character backstage, 2 or 3 over in the GF/SoG area, "Sarge" on the on/off ramp, and then 1 or 2 in Epcot. Those rough locations should still hold true as I've found them to be fairly consistent even through the other races with the same course.
2016 Marathon Weekend
Character recap
5K
Chip/Dale road by the boneyard
Rafiki in Africa outpost
Bolt in USA
Marie in France
Lilo/Stitch (swapped out) by Character Spot (normal Chip/Dale M&G location)
10K
Anna/Elsa on overpass ~.25M
Darkwing/Launchpad ~.6M
Atta/Flik 1M
Mulan/Mushu - China
Remy/Emile - France
Mike/Sully - ESPN Club
Tweedles - International Gateway
Phineas/Ferb - Character Spot
Half
Wreck it Ralph/Venelope by old speedway turn
Oogie Boogie
Mike/Sully in Tommorowland
Tweedles/Queen of Hearts - Teacups
Mime/Villains from Rapunzel FoF float by Friars Nook
Anna/Elsa on castle
Clarabelle Cow by Country Bears
Hook/Smee/Peter Pan/Wendy/Lost Boys w/Pan FoF float by parade barn (along with Croc float)
Mary Poppins/Bert/Penguins by GF
Stitch
Golf Goofy
Random streetmosphere golfers fighting Ginger
Green army men - hill to overpass
Tourist Genie - By Showcase Plaza where we round the planter
Full
Chicken Little/Abby Mallard - by old speedway straight
Wreck it Ralph/Venelope by old speedway turn
Jack/Sally
Lilo/Stich in Tomorrowland
White Rabbit/Alice - Teacups
Sebastian/Ariel w/legs - Ariel ride
Cogsworth - Belle's cottage
Anna/Elsa/Kristoff on castle
Louis/Tiana/Naveen - Liberty Square
Liver Lips/Big Al/?? - Country Bears
Bear Rabbit/Brer Bear/Brer Fox - Briar Patch gift store
Malificent float from FoF w/stilt walkers/dancers by parade barn
Mary Poppins
Golf Goofy
Random streetmosphere golfers fighting Ginger
Hades - After turn right off world drive heading towards AK
Old Hag (break just when I got there)
Shan-Yu (ditto)
Jack Sparrow/Barbosa w/pirate ship just before sewage treatment
Jafar (just before new dogleg)
Random streetmosphere tourists w/RV at end of dogleg
Timon - backstage at AK
King Louie/Baloo in Asiaish
Brer Bear just before Dinorama exit gate
Grave diggers ~14.6M
Phineas/Ferb
Koda/Kenai ~16.6M
Soccer Mickey bottom of WWoS stairs
Baseball Donald WWoS
ref/ump Chip&Dale WWoS
Random streetmosphere fishermen WWoS
Green Army men - DHS overpass
The Incredibles - DHS backstage before tunnel
Boo - DHS after tunnel
Sully - by Monster Inc M&G
Tourist Genie - Atlantic Dance Club area
Aurora - France
Belle - France
Jasmie - Morocco
Snow White - Germany
Mulan - China
Uncle Scrooge - Showcase plaza area
2017 Marathon Weekend
Character Recap
5k
Pre race - Pluto and Dopey
Thumper was on the backstage road
Vikings in Norway
Minnie in Italy
Chip and Dale w/fez in Morocco
Flannel Donald in Canada
Space Goofy by Club Cool
10k
Pre race - Minnie and Dopey
Launchpad and Scrooge at end of dogleg
Lilo and Stitch
Vikings in Norway
Travel Genie in Morocco
Revolutionary Mickey, Donald and Goofy in USA
Pluto at ESPN Club
Pooh and Tigger by backstage gate
Full
Pre race - Goofy, Daisy, Dopey, Chip and Dale
Captain Barbosa and Jack Sparrow
Lightning & Tow Mater
Jack and Sally
Buzz in Tommorowland
Tweedles by Tea Party
Snake Charmer Donald by Circus entryway
Beast at Be Our Guest
Frozen in castle rampart
Country Bears in Frontierland
Magnificent FoF float + thorn stiltwalkers backstage
Penguins by Grand Floridian
Travel Genie by golf course
Groomsmen by wedding pavillion
Lilo and Stitch
Big Bad Wolf
Attraction Museum
60s Tourists
Venelope and Ralph before sewage treatment
Clarabell and Horace at Horticulture
AK Animals from Affection Section
Meeko by train
Timon going onstage in Africa
King Louie by Flights of Wonder
Chester & Hester in Dinorama
Grave Diggers by AK overpass
Archeologists w/TRex skull by construction
Soccer Mickey and Cheerleader Minnie
Ref Chip, Dale and Donald
Sport Goofy on track
Joy and Sadness before stadium
Sarge on DHS overpass
Oswald in F! Entryway
Belle in France
Snow White in Germany
Prince Ali & Princess Jasmine in Morocco
Mulan in China
