My intention with my first Sims 4 Sim was to explore the entire game. I had her and her husband take on different branches of the same career, then every generation I was going to choose another career and have my heir and their spouse take on different branches. I only made it to the third generation because I've wandered off and started new saves about a zillion times, but the intention was there.
Maybe pick a town, set your family there, and explore whatever's related to that town. When you're ready to do something new, give your Sims a makeover and move them to another town, then do everything there. My version was starting a new save every time a pack came out, but you could do it all with the same family if you wanted.