Unfold the spoilers to get the information you need!
Background Info*** Spoiler - click to reveal ***
There are 500 online challenges in the game. We only need 250.
However there are 70 Bike challenges that won't count for this achievement. So we are left with 430 challenges to choose from. They are categorised as such:
2 players: 50 Freeburn Challenges + 10 Timed Challenges
3 players: 50 Freeburn Challenges + 10 Timed Challenges
4 players: 50 Freeburn Challenges + 10 Timed Challenges
5 players: 50 Freeburn Challenges + 10 Timed Challenges
6 players: 50 Freeburn Challenges + 10 Timed Challenges
7 players: 50 Freeburn Challenges + 10 Timed Challenges
8 players: 50 Freeburn Challenges + 10 Timed Challenges
2-8 players: 10 Island challenges
To get to the 250 I advise you to do 5 sets of 50. You could push for 4 sets of 60 and include the island challenges but reality shows that you'll get some stray challenges done anyway when going for other achievements
Order of the challenges - Boosting sessions
*** Spoiler - click to reveal ***If you follow the list of challenges from 1 to 50 you'll drive all over the place and get to the same places many times. Therefore I restructured the Freeburn Challenges in an spread sheet so they are more aligned in a route.
The route is very well calibrated and adjusted for every list of 50 challenges.
The Timed Challenges are not included because they always require two locations. I highly recommend using them as filler
The spreadsheet can be found here
https://docs.google.com/spreadsheets/d/14g4-Z9Osry2Agiz334Yj...If you prefer to just read it here then open the spoilers
2 player
*** Spoiler - click to reveal ***27 On The Waterfront
37 Into Space
35 Wave Jumping
28 Beachfront Rolls
33 Near Miss Chain
48 Power Parking
36 Find Space
38 Off The Rails
9 Crash Bridge
11 Fountain Missed
34 Drift and Near Miss
6 Go Clubbing
4 Oncoming Intro
7 Near Miss Intro
47 Eyes Bleed
39 Chain Gang
32 The I-88 Freeway
2 Get Social
1 Go Crash!
12 In The Navy
13 Jumping Express
46 Express Yourself
43 Drift and Shout
45 Long Jumpers
15 Mineheads
20 Drifters
5 Drift Intro
26 Flat Spin Intro
44 180!
30 Minute Man!
29 Boost Chain
3 Go Jump!
8 Jump Intro
17 Rock and Rolls!
16 Splashdown
14 Jump Casey
50 Hoop-la
25 Barrel Hoop
24 Air Hoop
40 Read Double
23 High Jump
21 Nelson Oncoming
19 Air Time on Uphill
41 720!
22 Dare to Jump!
42 Hole in One!
18 Drift Track
49 Billboard Top 10
10 Smash and Grab
31 Boardwalk
3 player
*** Spoiler - click to reveal ***48 City Sights
13 Flight Time
5 Coastguards
31 Beachfront Display
11 Barrel Roll
38 Traffic Calming
34 Draw Jumping
33 Splash Drift
4 Drift Intro
30 Ocean View Spins
28 Tunnel Vision
47 Keep It Going
7 Oncoming Intro
8 5 Near Misses
36 Near Miss Chain
32 O2K
35 Go Wildcats!
14 Go Ahead, Jump!
50 Check It Out!
49 1st Street Reverse
46 Ready To Tumble
40 Fish and Flips
16 Jump Bridge
41 Express Jumps
42 Reverse Cliff Top
18 Earth Movers
1 Boost Baby
29 15 Second Burn
9 All Drift
12 20 Second Run
39 Countdown
3 Get Air Time
15 Flat Spin Intro
6 Jump Co-op
27 Long Jump
10 Co-op Air Time
43 Rockfalls
17 Waterworks
24 Airfield Marathon
26 Hoops of Glory
25 Air Prox
23 Barn Busters
44 Jump For Your Life
45 Sky Driver
22 Windy Spinner
21 Fly on the Edge
19 The Paradise Job
20 Uphill Jumps
37 Co-op Smash
2 Driver Destruction
4 player
*** Spoiler - click to reveal ***33 Hot Tin Roof
1 4 Way Play
8 Pave Paradise
34 Stop Spot
2 Near Miss Intro
27 Railway Roller
10 Drawing Lots
25 Quick Draw
6 Go Clubbing
26 Newton Drift
35 Tunnel of Shove
49 Trail Blazers
28 Freeway Oncoming
29 Strike!
32 Reverse Break
24 Four-site
23 In The Navy
22 Jump and Miss
37 Flat Spin To Win
38 We Have Lift Off!
43 Dam Blast!
42 Rockridge Spins
30 Right Angled Roll
41 Quarry Rolls
3 Drift It
20 All Fired Up
7 Fast or Last
44 Inferno
5 Air time
13 Look and Leap
4 50 Yard Jump
9 Jump Distance
31 Drift 4 Fun
40 Mined the Gap!
36 Crashworks
50 Barrel Hoopla
12 12k Drift
11 Airfield Air Time
48 Thru Hoop
15 Island Hopping
16 Victory!
17 Barrel of Laughs
46 Flatspinners
45 Step On!
19 Uphill Struggle
18 Stay On Target
21 The Rock Hole
39 Dirt Buster
14 Billboard Intro
47 Smash!
5 player
*** Spoiler - click to reveal ***32 Rooftop Jumps
10 Wharf Speed
27 Coastguards
31 Beachcomber
28 Beachfront Pose
47 Beach Jump Reverse
46 Park It
29 Park Mayhem
34 Troubled Waters
30 1K Fountain
33 Drift & Near Miss
45 Step Over
6 Freeway Your Way
8 Flash In The Pan
1 Near Miss Intro
48 Are We There Yet?
49 Rapid View
26 Flame Trail
5 Run The Traffic
36 Pier Jump
35 Site Seeing
37 Oncoming Express
38 Express Whirl
21 8 Track!
11 Lone Stallion
39 Rockridge Rumble
40 Double Roll
25 Jump Far
15 Long Distance Fall
9 Single Roll
3 Drift Intro
4 5 Jump
7 Air Time!
20 Mine's A Jump
12 Work It!
22 Airfield Action
41 Low Flying
44 Ringo
50 Roll Thru Hoop
23 Carwrecked!
42 Lake Challenge
18 Hang Tough
43 Afterburner
19 High Five
14 Living On The Edge
13 Going Underground
17 Hot Stepper
16 Drop Off Uphill
2 Billboard Intro
24 Smashing!
6 player
*** Spoiler - click to reveal ***15 On The Waterfront
42 Meet and Greet
7 Barrel Roll Intro
40 Can You Make It?
41 Sandy Display
9 Skyrise
2 Go Clubbing
5 Drift Intro
1 Floor It
4 Near Miss Intro
8 Oncoming!
11 Freeway 500
12 Foot Down
14 Near Miss Ton
37 Missing Link
38 In your Face
10 Baseball Crash
39 Spray and Display
36 In the Navy
17 South Bay
43 Expresso
25 All Jump
34 6 Cars-a-Leaping
3 Jump Intro
13 Spin Doktor
16 Co-op Jumps
22 Hole Lotta Jumps
23 Open Face-Off
24 Blast Off!
31 Co-op Drift
33 Rock And Roll
26 Airfield Rollers
27 Airfield Spins
48 Airfield Reversal
49 Flying Thru
50 Rolling Hoop
28 Pass You By
30 Burn the Barn
29 Rouse Long Jump
21 Read and Roll
32 All Together Now
46 Off Track
45 Spin City
19 In A Tube
20 Uphill Flight
44 Stone Poses
18 Round & Round
35 Dirt Track Marathon
6 Billboard Intro
47 Billboard Hunt
7 player
*** Spoiler - click to reveal ***49 Fly for Webster!
34 Coastguards
5 Beachfront Aerials
28 Rolling Stock
30 Quick Park
31 Quick Draw
29 Newton Slide
32 Step To It
48 Burnouts
3 Boost Intro
6 Near Miss Intro
13 Time to Boost
27 Sim Freeway
25 Wrong Way A Long Way
26 Near Miss I-88
10 Go Wildcats!
33 Pier
46 South Bay Express
20 Express Race
11 Lone Stallion
43 Drift and Dirt
41 3K Leap
44 Half Century
19 Don't Quarry
7 Drift Intro
8 My Lovely Jumps
15 Co-op Jump
2 Air Time
35 Head Spins
9 7th Heaven
1 Fast Start
40 Quarry Barrels
42 Quarry Takeoffs
47 Dam
14 Water Water
22 Airfield Drift
38 Wide Body
45 Shooting Hoops
24 Airfield Angle
23 Airfield Display
21 Lost
36 Barnstorming
17 Read Roller
39 Burnout Way
18 High Jump
16 Air Today...
12 Tube Ride
4 Billboard Intro
37 Valley Hunt
50 4 Billboards
8 player
*** Spoiler - click to reveal ***41 On The Waterfront
49 Angus Leap
12 Wharf Loops
8 Barrel Roll Intro
9 Stuntman!
42 Find A Space
15 Parking Problem
11 Paradise Jump
43 Step Over
46 Fast Fuel
10 Over A Mile
5 Near Miss Intro
17 Rush Hour
1 Quick Fire
16 Quick Burst
29 Boost Chase
40 Hold The Button
18 Simple...
2 Batter Up
20 Pier Pressure
13 In The Navy
19 Floor Filler
36 Miracle Mile
14 Mr Bridger
35 Dirt Track Smash
23 Dirt Track Fun
26 Mountain Miss
31 Co-op Drift
34 What A Blast!
4 Learn to Drift
7 50 Yard Jump
30 Long Co-op Jumps
3 Co-op Jump Distance
24 Don't Look Down
21 Dam Co-op
22 Waterworks
50 Roller Hoop
37 Lift-Off
39 Go Around
44 Hoop Dreams
38 Rolling
47 The Island
33 Fill The Barn!
28 Jump High
27 Wind Farm Meet
45 Dead Man's Reverse
48 Edgy
25 Tube Train
32 Billboards... Go!
6 Billboard Intro
Order of the challenges - With randoms.
Always look at the first 12 challenges of the list and make your selection. Usually they are very easy such as activating your boost or doing any jump. Good option for filler challenges in my opinion