Grand Theft Auto: San Andreas Definitive Edition isn’t a super challenging game, but it can be a long one, due to them adding some extra trophies/achievements. For example, in the PS3/360 remaster and original PS4 port, there was no trophy/achievement for getting 100%, which made things a little easier. However, the Definitive Edition not only adds a 100% trophy/achievement, but also some that require you to do specific things during some missions. Since San Andreas doesn’t offer the ability to replay missions, like GTA5, then you will need to be very careful not to finish those missions without doing those objectives.
Stage 1 - Play Through the Main Story*
The first stage of the roadmap is to simply play through the main story, while paying attention to the specific missions that require doing specific actions. Thankfully, there’s only three such missions, which are Madd Dogg’s Rhymes, Mike Toreno, and Black Project, so make sure you have a separate save before each of those missions, in case you mess up the objective. In addition to worrying about the above, you will want to work on doing things like the Vehicle Missions, as they are extremely beneficial to you in the long run. The Paramedic one gives you more health, while the Vigilante one will give you more armor.
Stage 2 - Find All Collectibles
While doing the collectibles as you come across each new area is best, you can save them for after completing the main story. One reason why you might want to do them as soon as possible is because collecting all of one set will usually unlock guns for you to use during missions. For example, tagging all of the graffiti in Los Santos will unlock four weapons at your house on Grove Street, meaning you don’t have to waste time finding weapon pickups if you get Busted or Wasted. You will need to only do the following collectibles, since Unique Jumps don’t contribute to any trophies/achievements, nor 100%:
Stage 3 - Work on 100% Completion
With the collectibles and main story missions out of the way, you can begin working on the in-game 100% completion list. For a complete list of what is needed for 100%, visit the What’s Needed for 100%? page.
Stage 4 - Miscellaneous Trophies/Achievements
The final stage is just cleaning up the rest of the trophies/achievements. This includes anything not listed above, like getting eating at Cluckin’ Bell eight times, and whatever else. Some of these can be done during other steps and may even unlock naturally then, too.