@rif3j0qhpi1h The mods I linked don't add any meaningful overhead to the game, and in fact they improve performance by cleaning up junk that could otherwise cause problems that take the game engine extra resources to resolve. (Some issues the game can't resolve on its own as well.) For example, Overwatch will reset a stuck sim before the game itself does, and when there's a stuck sim, the engine will fall all over itself trying and failing to reroute the sim.
For the camera issue, camera controls in this version of Sims 3 have always been problematic. The only real suggestion I have is to shift the camera by right-clicking instead, or edge scrolling if you play in fullscreen mode.
For the crashing, is this in a brand-new save, or one that you've been playing for a while? What world are you playing in? Please also list the full specs of your Mac—everything under About This Mac including the OS and except for the serial number—and the expansion packs you currently have installed.