I won't call it mastersave since you have to complete the first mission "Luigi's Girls" to enable the saving of the game.
It's every side-mission possible at this point done before making the 2nd mission "Dont Spank Ma Bitch Up" in a total 53% progress in the game
Paramedic is done
20 criminals killed for Vigilante mission on each Island (in a row on both Portland and Staunton Island)
20 fires extinguished for Firefighter mission on each Island (in a row on both Portland and Staunton Island)
100 fares for Taxi mission in a row
All Hidden Packages collected
All Unique Jumps done
All Rampages completed
RC Missions completed
Patriot Playground completed
A Ride In The Park completed
Multistporey Mayhem completed
Gripped! completed
All vehicles delivered at Portland's import/export garage
All vehicles except for BF Injection delivered at Shoreside Vale's import/export garage
All vehicles except for FBI Car and Rhino delievered to Emergency Vehicle Crane
Maximum Criminal Rating possible at this time 3521 points (Executioner)
1.002.981.693$ (obtained through firefighter glitch)
DP UC Kuruma stored in Shoreside Vale
DP - crashproof
UC - unique color