The safest way to get a portable version is to create one yourself by compressing your own legitimate copy of the game. However, if you are looking for a pre-compressed RAR file, look for trusted repackers. One of the most famous highly-compressed versions comes from the creator "FitGirl" or similar repack sites.
(Las Vegas)—alongside vast countryside and mountain regions. Deep Character Customization: Carl "CJ" Johnson's Gta San Andreas Portable Pc Rar
If you love the game, consider buying the official version on Steam during a sale (it often drops to under $3). This guarantees you get all the radio stations, high-definition cutscenes, and Steam Cloud saves without worrying about viruses. The safest way to get a portable version
If you own the original game legally, you can create your own portable version: Gta San Andreas Portable Pc Rar